Is there a better way to accelerate particles?

Daniel and Jorge talk about why its so expensive to build a super collider and how plasma technology might make it all better, faster, cheaper. 

See omnystudio.com/listener for privacy information.

Episode Transcript

Speaker 1 (00:08):
Hey, Daniel, how much did the last particle accelerator cost?
The LHC had a price tag of about ten billion dollars? Oh?
Is that it? And how much will the next one cost?
Something like fifty to one hundred billion, depending on the design.
Fifty to one hundred you can narrow it down a
little bit. It's a fifty billion dollars difference there, and

(00:29):
we'd be happy with fifty billion, thank you very much.
I guess who's going to pay for it? We were
going to send a request to the cartoonists of the world.
You want cartoonists to pay for physics? You'd be the
other way around. I feel like I guess we are
constantly violating the laws of physics in cartoons, so why
would you pay us? You guys are just rolling in it,
aren't you? Rolling in? Some But maybe you should scale

(00:51):
down your ambitions so it's not as expensive. Well, you know,
we want to solve the deepest mysteries of the universe.
How do you scale down those ambitions? Isn't that kind
of your job? Things? Putting things into perspective, shrinking down
thanks to the quantum level, and I want to scale
our ten billion dollar budget to one hundred billion dollars
in quantum coins or what in bitcoins or cue bitcoins.

(01:13):
There's definitely a lot of uncertainty in whether we'll ever
get that money, both the scam and legit kind of currency.

(01:34):
Hi am Jorhemakirtiness and the creator of PhD comics. Hi.
I'm Daniel. I'm a particle physicist and a professor at
UC Irvine, and I want all the science projects to
get more money, really all of them. I'm sure there
are some science projects you're like, M, I don't know
if we should do that. As long as they qualify
as science projects, I think we should invest in them.
You know, the big government funding agencies. They get inundated

(01:56):
in proposals every year, and a lot of them are
really good ideas that they have to say no too
because they don't have enough money. Yeah, that is pretty sad.
There should be more money for science, right. Science is
usually good, usually right, and your also are pretty good
at doing something good. Yeah, it doesn't matter if you're
studying the mating patterns of ducks or the formation of
the Earth or what's inside black hole. You are feeding

(02:19):
the curiosity of humanity, and history shows us that that
is a good investment. So sometimes people pitch scientists against
other scientists, saying like who should get this money? But
I think we should all get the money, even the cartoonists.
The science of cartoons. I guess that's a different agency
in the government. But anyways, welcome to our podcast Daniel

(02:39):
and Jorge Explain the Universe, a production of iHeartRadio in
which we use science to try to push back the
boundaries of human ignorance. We are amazed at this incredible
and wonderful and beautiful universe that we find ourselves in,
but we want to do more than just appreciate it.
We want to understand it. We want to decode its
mysteries and explain all of them to you. That's right.

(03:01):
It is a pretty amazing universe. And if you invest
in our of your time here with us today, we
hopefully we'll give your returns in terms of you understanding
how things work and appreciating this amazing and beautiful cosmos
that we live in. That's right. Although you're welcome to
invest more than just an hour of your time. Send
us some cash, no problem. Do you take bitcoins or
cue bitcoins, Hey, I'll take any donations from my science

(03:24):
absolutely make out a check just too expressive, Daniel. Have
you thought of maybe if you reduce your prices, people
will invest more in it. I would love to make
science cheaper. You know, something that limits our understanding the
universe is really just how much money we spend on it.
It's like we're in the science candy store and we
just have pennies in our pockets. But if we could
figure out a way and make it all cheaper than wow,

(03:46):
we could just buy more secrets of the universe. What
a day that would be. Yeah, it sounds awesome, although
they say it all starts with the individuals, Daniel. So
you know, should we tell your university to cut your
salary so I should do half as much physics? Well,
you know you could do twice as much for half

(04:06):
the price. Yeah, and then I'll eat half as much. Right, Sorry, kids,
you're not eating today. It's a Tuesday, and it's for science,
so you could do it too. For Yeah, you could
do a hunger experiment and also make size cheaper. For
you know, the mating patterns of certain animals in certain places.
Sounds like we could learn a lot, but learn we

(04:27):
do aim to do here on the podcast and so
there's the rest of humanity in terms of understanding the universe,
from the immense galaxies out there floating in space to
the tiny little particles that make up your body and
everything that you touch on an everyday basis. That's right,
and we have a few ways of understanding the universe.
One thing we can do is just look out into
the universe and find interesting stuff that's happening and try

(04:49):
to learn from it. That's what astrophysicists have to do,
because as much as they want to shoot black holes
at each other, they don't have a black hole collider,
so they have to wait for nature to set up
and do it for them. The other approach, of course,
is to try to create the conditions we want to
study here on Earth, to set up the experiments that
might force the universe to reveal one of its secrets

(05:11):
to us. Yeah, and one of those strategies is to
basically smash things together, is to collide tiny little particles
and kind of see how you can break them. I
guess that's kind of what you're trying to do, right,
is you're trying to break little particles. Yeah, we are
trying to break little particles. Essentially, we are trying to
create new conditions that reveal the laws of physics. You know,
we have a lot of experience with sort of slow

(05:32):
moving cold stuff like baseballs flying through the air or
things swimming through the ocean. Things aren't moving very very fast,
they don't have a whole lot of energy. So we
think we understand that kind of physics. But we want
to understand the physics of the whole universe. We want
to understand what happens when you push things really really far,
when you get really really small. And in order to
do that, we have to create those conditions. So we

(05:53):
smash tiny particles together to make these really dense little
blobs of energy that we hope reveal what the sort
of underlying truths of the universe is. I guess, yeah,
you're not really trying to break particles. You're trying to
kind of smush them together and then see what the
universe does with that smooth the energy. Yeah, when particles
get really close together, they interact, and that interaction can

(06:14):
create new kinds of particles. One of the most amazing
things about particle collisions is that it's not like chemistry.
When you're doing chemistry, you combine like H two and
O two to make water. All the bits that went
in just get rearranged. Right, Every hydrogen nucleus that was
there is still there. Every oxygen atom that was there
is still there. But when we do particle collisions, that's

(06:35):
not what happens. What comes out of the collisions, it's
not just like a rearrangement of the bits that went
in like some big Lego project. Those particles that go
into the collisions, they get literally annihilated and turned into
new kinds of matter. So we're not doing chemistry. We're
doing alchemy. Although that's kind of what you think is happening, right, Like,
you don't know, you're not quite sure. Maybe inside of

(06:57):
those little tiny particles are tiny little strength that do
get kind of rearranged like legos. Isn't that a possibility? Absolutely,
that's right. There are many layers to our picture of
the universe. Currently, we think about the particles that are
interacting those quarks and the electrons as if they are
fundamental objects. But it certainly might be that they are emerging,
that there are combinations of even smaller things, and so

(07:17):
then what it means to annihilate that particle is in fact,
to break it into its smaller components, which then can
rearrange themselves. But if we can do that, then we
hope to smash those components together and maybe annihilate them,
and eventually we think when you get down to the
universe and its most basic building block, what you're really
doing is annihilation of fundamental objects. So you're an annihilist

(07:41):
at heart, you're an annihilist physicist, I am an annihilist, absolutely, Yeah,
you subscribe to annihilism. Hey, at least it's an ethos, right,
you should come up with your own kind of a
punk rock music for that. But smashing these things together,
I guess it's one thing that you can learn how
things work, because I guess when things are that small,
you can't take a pair of tweezers and pry them open, right, Like,

(08:02):
That's kind of the only way you can really see
what's inside of some of these fundamental particles. Yeah, and
you really put your finger there on what we're trying
to do. We're trying to see inside these particles. I mean,
from one perspective, you could say you're annihilating them. From
another perspective, you could say you're tearing them open. You're
destroying the arrangement of whatever the smaller bits are, that
is the electron or the quark. In the end, what

(08:23):
we're trying to do is pull them apart, and fundamentally,
it's not that different from using tweezers. What do tweezers do.
They apply a lot of force in one's very specific
energy in order to break some bonds, and that's exactly
what we're trying to do with these particles. We smash
one proton against the other one, hoping that the high
energy that the proton has will smash open the other proton,

(08:44):
revealing what's inside of it, and maybe even the quark
smashing together will reveal what's inside of them. Well, smashing
you have been doing at the Large Hadron collider or
you were right now you have sort of an appointment there,
that's right. My main research program when I'm not gooving
off doing podcasts or other projects, is annihilating protons at
the Large Hadron collider. I'm remember the Atlas experiment, which

(09:05):
has built a huge electronic device which wraps around the
point of collisions to take pictures of all the particles
that fly out and try to learn things about what
happened in all of those collisions. Yeah, And the whole
point of the accelerator is to basically accelerate particles. You're
speeding up the particles from standing still to almost at
the speed of light, or at least at a very

(09:27):
high velocity, and then you smash it together to get
higher and higher energies. But I guess maybe the problem
is that the LHC is kind of showing its age
now a little bit. Yeah, that's right. The LHC is big,
and it's powerful, and it was expensive, but it's also
limited in its ability. The way we talk about these
accelerators is basically by quoting their top speed the most

(09:48):
energy that we can put into the particles that we're
smashing together. The reason that that's the most interesting number,
the one that really tells us like the discovery potential
of this device, is because it limits the kind of
things that it can create. Like, you take those two particles,
you smash them together. What else can you make? Well,
you might be able to have two other electrons come out,
or two other quarks, or something else we already know about.

(10:10):
But if you have enough energy, you might be able
to build something new. Something we haven't seen before because
it requires more energy density than typically exists in the universe.
So the more energy you have in your collider, the
more you have access to like Nature's hidden menu of particles,
things that can exist in the universe but don't typically

(10:31):
because there aren't the conditions to make them. So the
LATEC is big and it's powerful, but it doesn't have
infinite energy. Yeah. Well, at the time it was built,
it did sort of break I mean, it definitely broke
new ground in terms of how much energy you could
get in an experiment. But I guess you random LAC
and it found the exploson and all these amazing discoveries,
and now you're kind of thinking about what's next, how

(10:52):
can we get more energy? Yeah, we're always thinking about
what's next. The collider that came just before the LATEC
was just outside Chicago is the Tevatron about two terra
electron volts and the Large Hadron Collider has about thirteen
tera electron volts. And that's a big jump, right, that's
like almost a factor of seven in terms of the
territory we could explore and imagine, for example, multiplying the

(11:15):
territory you've explored by a factor of seven. If you're
in the field of like geology or planetary astronomy, you've
only ever looked at Earth, and now you can simultaneously
land on seven new planets all at the same time
and see what's there and learn all about it. So
when we turned on the Large Hadron Collider, it's like
we multiplied by a factor of seven the sort of

(11:35):
size of the particle universe that we were able to
explore and to look at, and we didn't know what
was there. Every time we do these kinds of explorations,
there could be huge surprises waiting for us, or sort
of nothing. And as you say, we found the Higgs boson,
but we've been running for quite a few years and
we haven't found anything else since then. Now we're wondering, like, hmm,
what's around the next corner if we crack open another

(11:58):
energy range, will there be for easy discoveries waiting for us,
or just more dust and rubble. Yeah, So the LC
sort of got you to a certain level, which was amazing,
But I guess you feel like you've already explored this level.
You've looked into every corner of this energy level, and
you're kind of feeling like there's nothing else here. That's
a very delicate political question as we seek approval for

(12:21):
running the large changer on cloder for another fifteen years,
because we're trying to make the science case that running
it for a lot longer can look for really rare
particles that maybe we missed in sort of the first scoop.
So we're sort of going in two directions at once.
One group of people is like, let's run this thing
for as long as possible and maybe look for really
rare stuff we might have missed, and the other group
is looking towards the future and saying, can we build

(12:44):
the next one? Can we plan now for the super LHC?
The super LHC nice sounds like a like a superhero. Well,
I guess the problem is that the LC was it's big,
and it was a little expensive. But now if you
want to get into higher energies, it gets even bigger
and more expensive, right with the same technology it does. Basically,

(13:04):
the only thing that limits us from building a bigger accelerator,
or from having built one instead of the LATEC is money.
The cost of the accelerator just scales with the size,
sort of like building a highway. It's like a million
dollars per mile. More miles means some more millions of dollars.
So you want more energy, you've got to build a
bigger collider, which costs more money. And so now people

(13:25):
are wondering, like, should we just spend ten times as
much money on a super duper version of this or
should we figure out a cheaper way to do it? Yeah,
because I guess, first of all, you'll know that I say,
with the existing technology, it's going to be a bigger
and more expensive and also I don't think most scientists
are going to cut their salary and have it makes

(13:46):
a cheaper endeavor. So I guess, like you said, we
have to start looking at maybe new technologies. So today
on the podcast, we'll be asking the question, is there
a better way to accelerate particles? I guess that you've
been using one way to accelerate particles all this time
or several ways. Right, We've been accelerating particles since about

(14:08):
the nineteen thirties, and we've had a series of sort
of technological revolutions. People come up with a new idea
to make them more powerful, and we get like a
big jump in energy we're sort of at the end
of one of those cycles. We've been doing it the
same way for a few decades now, and we can
get sort of like little incremental increases without just making
it bigger, and so it sort of feels like about

(14:29):
the time that we need to jump to the next
technology and figure out like a whole new way to
do this kind of thing. Yeah, like, if maybe the
engineers figure out a better way to get particles moving,
you could maybe make accelerators that are at the same
energy or more but a lot cheaper, right, That's the
whole point, And maybe eventually you'll just have it on
your phone. Eventually there's an app for that, perhaps for

(14:52):
shooting lightspeed particles from your phone. That seems usable. Well,
you do have a light speed accelerator on your phone
right now, I mean you have a flashlight literally shoots
out particles at light speed. Unfortunately not high enough energy
to do any interesting physics. But yeah, the dream is like,
instead of having to collaborate with five thousand people from
all over the world on a ten billion dollar project,

(15:12):
why can't I just build this thing on a tabletop
in my own basement or in my lab here at
you see Irvine for two hundred thousand dollars or something
and run my own experiments. Why can't everybody have their
own plank scale particle collider to explore the nature of
the universe? Well, I can't, and why shouldn't have? But
that's not the topic today. The topic is can that happen? Like,

(15:34):
can you imagine a future where you can have a
particle collider that's as powerful as the LHC, which is huge,
which is several kilometers along and underground. Can you maybe
have that in like a little box in your basement.
It's such a dream. I mean, imagine all of the
secrets we could learn, those secrets that are just out
there waiting for us if we only have the technology

(15:55):
to crack them open. It's like we're in a room
surrounded by locked boxes and we just don't have the
key to any of them. You need engineers to save
users say, we definitely do need the engineers working closely
with a physicist to figure this all out. Well, it's
usually we were wondering how many people have thought about
this question of whether or not there's maybe a better
way to accelerate particles. So thank you to everybody who

(16:16):
answers these questions for the podcast to give us a
sense for what people are thinking and what they already know.
If you'd like to participate for a future episode, please
don't be shy. Right to meet two questions at Daniel
Nhorge dot com. So think about it for a second.
Do you think there's a better way to accelerate particles.
Here's what people had to say. My understanding of current
method is that we apply electromagnetic field to accelerate a particle,

(16:41):
and then they are propelled in high velocities in a tunnel.
I'm not sure if there is any other way that
this could be done. There must be, of course, but
I don't think it will be that control and this
might be more physical when I have no clue how
that can be done well right away, I think about
the fact that particles go to incredible speeds when they're

(17:03):
orbiting a black hole in the ucretion disk. So maybe
gravity would be a better way to accelerate particles. I
just have no idea how we would go about doing that.
I think a better way to accelerate particles might be
to give it more energy or like heat, because if
you have a lot of energy you're going to be
moving fast. It also works the same way with heat,

(17:25):
because like if you're cold, you don't want to move,
you stay in the same place. I suppose if you
could get yourself a mini black hole and rip the
particles around the event horizon, they might speed up pretty good.
I was wondering when I asked these questions, what if
somebody actually came up with some super genius way to
do this, would I end up like collaborating with them,

(17:45):
or like, would they get the patent for it? I
mean it could have been Thorny whoa like would you
have to pay them as some of your salary? That
would be such a difficult question. I'd hire them on
the spot. Absolutely. There are some pretty interesting ideas here.
I think maybe there are, you know, maybe the next
big idea. It wasn't one of those answers. You think

(18:06):
the mini black hole is the solution of the problem. Yeah,
First build a super collider to create mini black holes.
Then use those mini black holes to accelerate particles. It's
like a bootstrap. Yeah yeah. Or gravity. That was kind
of an interesting idea. I mean, we use gravity all
the time to accelerate spacecraft, right, We definitely do use gravity, absolutely,
and gravity does accelerate particles like particles fall towards the

(18:29):
Earth all the time. They're called cosmic rays, and they
actually do achieve super high energies and create massive collisions
in the atmosphere that physicists study and used to try
to understand how particles interact and what it all means.
But those are a little more difficult to control. All right, Well,
it's an interesting question. How do we accelerate particles faster, cheaper,
and better? I guess cheaper, faster better? Isn't that the

(18:52):
goal of any industry exactly? And then making an app
how do we do physics cheaper, faster, bet Well, maybe
a step us through here, how do we currently accelerate particles?
Like how does the LHC exactly? How does it get
particles moving so fast? Well, I don't know if that
pun was intended or not, but we currently use electrical
currents to accelerate particles. Yes, that was totally on purpose.

(19:13):
I wasn't trying to app anything up or anything. I'm
just trying to be a positive, reinforcing partner on the podcast. Yes,
I'm just I'm also just trying to you know, kind
of work the field here. This is why we don't
charge for this podcast. Let's stop with the electrifinally terrible
punts here, Let's get down in nuts and bolts. How
are those nuts and bolts put together? In the LHC

(19:34):
moving past our magnetic senses of humor. Essentially, we can
only accelerate charged particles, and the reason is that we
use electric fields in order to do it. Electric fields
can tug on charge particles. That's essentially what they are.
And so the basics is, you want a particle moving fast,
you put it in an electric field. The voltage there

(19:54):
will accelerate the particle in one direction. That's like the
super basic initial version of a particle accelerator. Meaning basically
you set up like a magnet, right, and then you
have the magnet attract charge particles, and then that gets
the moving. Well, we do have magnets, but magnets actually
cannot accelerate particles. They can only bend them. They can
change their direction, but they can't speed them up. But

(20:16):
an electric field can actually accelerate something. And so, for example,
the old televisions that people used to watch, the ones
that are not flat screens, had an electron accelerator in
the back of them. Met a little gun that would
accelerate electrons across an electric field and shoot it at
the back of the screen, and that's what actually made
the images. So everybody used to have their own little

(20:37):
particle accelerator in their house shooting into their brains extray night,
and that uses an electric field. It's basically a cathode tube.
We have a voltage applied and it boils electrons off
of one of the nodes and towards the other one.
But I guess what I'm saying, it basically works like
a magnet, right, cathay tube is basically you're using magnetism
to move the electrons along. Yeah, I mean you're using

(20:59):
electromagnetism more generally, using the electric field to accelerate it,
and then you had a magnet in order to steer
the electrons. So yeah, absolutely, it's all electromagnetism. And that's why,
for example, we have proton accelerators and electron accelerators. We
don't have neutron accelerators or neutral atom accelerators because things
have to have a charge in order for an electric

(21:19):
field to push on them. Yeah, I guess just kind
of generally, that's how things push and pull most of
the time you're here on Earth, right, Like when I
pick up a glass of water, or when you push
on the door, you're really using electromagnetic forces to push
those things. Yeah, that's absolutely right. A baseball is tugged
by gravity, but most of the interactions you have are
really electromagnetic interactions. The electrons that the tip of your

(21:42):
finger are pushing against the electrons in the wall and resisting.
That's why things seem to be solid, because the forces
that fill the space between the tiny little particles, that's
what gives volume volume, and so that's what constructs our world. Absolutely,
it would be a very very different world without electromagnetic force. Yeah,
you just made me realize, like all the neutrons in

(22:02):
our bodies and the objects around is, we're not really
pushing them directly, right, Like, it's more like our electrons
are pushing the electrons and those atoms, and those electrons
are pushing the protons in the nucleus, and then those
are the ones that are pushing on the neutrons inside
of atoms. Yeah, the protons and the neutrons stick together
using the strong force, and so that's what clumps them together. Yeah,
it's all a big dance of the forces we've discovered

(22:24):
to make the world that we know and love. All right, well,
that's the basic way that hilleriors work right now is
using electromagnetic fields. Let's get into a little bit more
detail about that and then also talk about maybe new
ways that we can get particles going for better and
more powerful colliders. But first let's take a quick break.

(22:53):
All right, we're talking about new accelerator technologies here, but
first we're talking about old accelerator technologies. And you said,
we've had this old technology sins the fifties, right or
fifties or thirties. So the very first accelerators were like
in the thirties and the forties. They got more powerful
in the fifties, which is what heralded like the era
of the particle zoo, as people were smashing particles together

(23:15):
at higher energies and discovering all sorts of stuff. But
it basically started with just accelerating things over a gap,
and then people tried to reuse that gap multiple times.
So like you know, if you go across that gap,
you speed up. Can we go across that gap more
than once. So they had accelerators called cyclotrons, where a
particle would go in a circle and go across the
gap multiple times. They had singotrons where you got even

(23:38):
more sophisticated and you would try to like sync up
the energy in the gap with when the particle was
going faster and faster. And so I think the basic
idea is that if you have an electron, First of all,
you sort of create an electron and you kind of
put it out there in space in the air by itself,
and then you basically hold a positive electric charge ahead
of it basically or a negative charge behind it, and

(23:58):
then that electro magnetic repulsion or attraction then moves your
electron forward, and that's how you get it going. Yeah,
that's basically how you do it. And you can imagine
doing that with like a battery. For example, a battery
can create that kind of voltage difference between two plates
by shuttling the electrons from one side to the other,
so that if you put an electron in the gap there,
it will get pushed towards the lower voltage and that's

(24:20):
what the acceleration is. So essentially you arrange the charges
to give you an electric field to push on an
electron and that will accelerate it. Yeah, like you said,
like in a battery, Like a battery will maybe concentrate
the electrons and a coil or a wire or plate
towards the back, and then that will push your single
electron forward. But there's only kind of so much that
you can push it, right doing it that way, Yeah,

(24:42):
there's only so much you can push it. You can
try to pump a lot of energy into that electric field,
but eventually things will break down. Like if you have
two pieces of metal and you put a really strong
electric field across them, Eventually it will pull the electrons
out of that metal and break down the electric field.
And then what you do is once the electron gets going,
then you use another electric field up ahead to accelerate

(25:05):
it even more. Yeah. So, because you can't put an
infinite amount of energy into a single one of these
sort of like little accelerators, because it'll break down the
way like lightning is like a breakdown of the voltage
between the air and the ground. Then you stack them up,
you say, well, I'm gonna have one and then might
have another one that might have another one that might
have another one you just sort of like line these
things up so that each one gives your electron a

(25:27):
little bit of a push. Yeah, And I guess initially
in the fifties they would use they would put these
in a straight line, right, Like you accelerate an electron
with one accelerator, and then the next one picks it
up and accelerate it even more, and you sort of
like a tunnel or a gun or like the barrel
of a rifle, and that gets your electrons going even faster. Exactly.
There's a little bit of a wrinkle there though, because

(25:49):
what happens when your electron passes a sort of negative
potential plate of the first one, is it wants to
slow down. If you imagine like a bunch of positive
charges there that are pulling the electron towards that first plate,
what happens when it passes it, Now those positive charges
are pulling it back. And so people develop these really
fancy techniques to oscillate the voltage across those plates so

(26:11):
that when the particles moving towards it pulling it towards it,
and then just as it passes it flips the charges
and pushes it away. So we have these like RF
cavities they're called. With these oscillating fields, there are time
perfectly to speed the particles up and then avoid slowing
them down. And as you say, the strategy to making
them bigger and longer and faster is just to stack

(26:31):
them up to make a big tunnel and put a
bunch of these in there. Yeah, that's how they did
it initially. But then at some point they figured out
that you can get even more acceleration by having the
particles going a circle and basically go through this accelerating
part multiple times, and then they can go faster and
faster and faster each time. Yeah. So the one design
of the accelerator is called a linear accelerator. There's one

(26:52):
like that at Stanford, there's one like that in Germany.
We just shoot them down a tunnel. It's a one go.
You speed them up, you get them to as fast
as you can, and then them at the end. But
another strategy is to reuse the tunnel by having a
go in a circle. And so as you say, you
have like something that gives it a kick, and then
you have something that bends it, and you have something
it gives it a kick, and then you have something
that bends it, and so the large hadron colliders like that.

(27:13):
It's a big circle and the particles move around a
tunnel and there's segments that push it and then segments
that bend it using very powerful magnets bend it, you mean,
like as in they make the particles kind of go
right a little bit and then then makes them go
in a circle. Yeah. So the particles move not actually
in a perfect circle, because they move in straight lines
through the little mini accelerator segments and then they bend

(27:36):
through the magnets. So it's more like a really big
polygon with a bunch of straight sides. Yeah, I guess
the difference it's sort of like the between a sling shot,
like you pull back and then you let go and
the rover bands throw the rock forward or whatever you're
trying to shoot and using a sling where you like
put the rock in a little sling and then you
spin and spin and spin, and each time you spin

(27:56):
it you make it go faster and then at some
point you let it go, you know. Or if going
to use like kid analogies, it's like the difference between
a slide. You start at the top and you go
fast and you hit the bottom or a merry go
round where your friend can keep pushing it faster and
faster and faster, and you're going around faster and faster
until you both throw up. And that's really what particle
physics is all about, right, throwing up what's inside of
the fundamental particles. Yeah, we're exploring the vomit frontier in

(28:19):
the end, it's right, your vomit physicists, nihilist vomiting physics.
And that's basically the technology. The large hadron collider is
pushing bend, pushing bend, push in bend. And what limits
the large hadron collider is essentially the size of the tunnel.
Building that kind of tunnel and filling it with all
that technology is expensive. But in order to get fast,
you gotta go big. Well, maybe to talk a little

(28:40):
bit about why it needs to be bigger, it's because
of the limitations in the magnets that bend the path
of the particles. Right, Like, if you can get stronger
magnets are a better way to kind of curve the
path of these particles, then you could have the same
circle but just have the particles go faster in it. Yeah,
if you had stronger magnet that could bend them more

(29:01):
effectively at the same speed. Then, yeah, you could have
a smaller circle, which means you could reuse the same
linear accelerating segments at the same magnets more times. Right,
So it would go around more times to get to
the same speed. But you could build a smaller device
instead of time to be like tens of kilometers around. Right,
this tunnel, the large change on collider is filled with

(29:21):
tens of kilometers of these things. Right, it's not a
small device. But if the magnets were more powerful and
you could bend it, then you could basically shrink the
size of that circle and the whole thing would be
smaller and cheaper, right, Because I guess the problem is
that the faster the particles go, the harder it is
to get them to go in a circle. Right, Because
the fasters are going the kind of more I guess

(29:41):
entrifical the force you need to kind of keep them
in a circle. Yeah, you need strong magnets to move
very high speed particles and a circle. It's a centripetal
force towards the center that keeps something moving in a circle,
the same way the Earth moves around the Sun because
of the force of gravity pulling it towards the Sun.
So we can make these particles kind of like orbit

(30:02):
the center of the collider using these magnets to bend
their path to provide that same kind of force, And
if we could provide a stronger force, we could bend
them in a tighter circle. Yeah. So like right now,
you probably could accelerate the particles faster, like you can't
make them go faster, but you wouldn't be able to
basically control them. Like if you accelerated them any faster,
they would basically go off the rails kind of right,

(30:24):
Like they would start hitting the walls of your collider
and that would burn them up, and then you'd poke
a hole in your tup tunnel and then the whole
thing goes That's right. We're limited either by the magnet
technology or by the size of the tunnel. Like we
can make the tunnel bigger with the same magnets and
then we could get the higher energy, or we could
make the tunnel smaller with stronger magnets to get to

(30:44):
the same energy. But if we had the same tunnel
and we just whizzed them around more and kept pushing
on them. Then eventually we would not be able to
contain them using our magnets. It would just slam into
the wall. So if you increase the energy, do you
have someone down there at the basement going she kind
of take any more cut? Yeah, that's a specific job, absolutely,

(31:06):
and you have to hire a scotchman from your collaboration
to do that one. No, we prefer Panamanians to do
a Scottish accent. Actually, oh yeah, that's just as good.
No comment for our Scottish listeners. But our magnet technology
is pretty awesome. I mean, we have super conducting magnets
down there. We're really pushing the limits of what magnets

(31:27):
can do. And so one way we could improve particle
colliders is to make some breakthrough in magnet technology to
make these things more powerful and smaller or cheaper. What's
the limitation, I guess is it just that the magnets.
You're already running as much current as you can through
these magnets or what, Yeah, we're running as much current
as we can without them breaking down. They're already cooled

(31:49):
down to a few degrees Calvin. So we can take
advantage of their super conducting nature, which means if we
get super duper strong magnets out of our current and
they don't like heat up and distort. Maybe you remember that,
and we turned on the large hende On collider. There
was a disaster in two thousand and nine, just a
few months in, and some of the liquid helium that
was keeping this thing cool sprayed out everywhere and the
whole thing warmed up, and it was a big disaster.

(32:11):
So these things are not easy to operate and to
keep functional. One of the many ways that the beam
can go wrong is something we call a quench, when
one of the magnets basically fails and the beam just
like gets dumped into the rock. And so we're really
operating at the limit of magnet technology. All right, Well,
then I guess the idea is that is there like
a revolutionary new technology or a totally different way of

(32:34):
doing the whole particle accelerating thing that could maybe like
let you get away with faster velocities without having these
gigantic tunnels and these superconducting magnets. Oh there is, and
I'm dying to talk about it. Well, steps through this, Danuel.
What is this amazing technology called and how does it work?
So the idea is, instead of making the magnet stronger,

(32:54):
can we make the accelerator part much more powerful? Can
we accelerate particles to much higher energies over a shorter distance.
I remember before the limitation was that we couldn't have
strong enough electric fields across two metal plates because it
would like make a breakdown between those plates. Remember that
right now, in our colliders, these particles are accelerated through

(33:14):
a vacuum. So between those plates, it's not like air,
So you're not getting like ionization of the air the
way you do when you have like static electricity or
lightning jumping from the ground to the earth. It's really
a pure breakdown of the metal, right You're like pulling
the electrons off of the metal. And so in order
to avoid this breakdown, people are thinking, well, maybe we
shouldn't have a vacuum, Maybe we should fill that with

(33:35):
something in order to avoid a breakdown. And so one
idea is to use a plasma instead of having a vacuum.
So let me see if I get this straight. It's
sort of like the same technology where you have plates,
like metal plates, and in these plates you basically like
run a current through them, so that you kind of
make a magnet basically, but now the twist is and
instead of having it in a vacuum, you put it

(33:56):
inside of a plasma. That's right, We use a plasma
instead of having a vacuum. But now we don't have
the external electric field provided by some plates. Now we
use the plasma itself to generate the electric fields internally.
So wait, there's no plates, there's no plates at all. No,
but we think that it's possible to generate much stronger
electric fields within the plasma than it is between two

(34:19):
metal plates and a vacuum. Okay, so you use the
plasma as the plate kind of m exactly. And so
you take this plasma and you like zap it with
a laser, which rearranges all the charges within the plasma
in such a way to create very strong electric fields
inside the plasma that can then be used to accelerate particles.
That's the basic idea. So what would this look like

(34:41):
A like a tube basically kind of or a tunnel
filled with plasma, and then you're shooting lasers into this
to create kind of like variations in the electric fields
inside of the plasma. Exactly. Remember that a plasma is
just really hot gas. Like you take hydrogen hydrogen as
a proton and electron. The electron is happily orbiting of
the nucleus the proton, and if you give that electron

(35:03):
more energy, it goes up an energy level sort of
larger orbital radius, and you keep doing that, eventually the
electron goes free. And so that's what a plasma is.
The electrons have so much energy that they're not bound
anymore to the protons. So it's a charged gas, right.
It has positive and negative charges all flowing around in it,
unlike neutral hydrogen, which is you know, protons and electrons

(35:25):
bound tightly together, so they're effectively neutral. So this plasma
is like microscopically charged, but typically it's like macroscopically neutral.
You take like a big chunk of it as the
same number of electrons and protons, but you can induce
waves in it. You can like pull on the electrons
or zap all the electrons, get them to move in
one direction, which will create an electric field within the plasma,

(35:47):
like you create you're creating a current of electrons inside
of the plasma. Is that what you mean? What you
actually do is create like a wake field inside of it,
so it's not literally a current, but yeah, you're creating
like these waves of electrons through the plasma. They're like
density waves where the electrons are like wiggling, and that
creates electromagnetic fields which you can then use to accelerate particles.

(36:08):
So you have this tube, as you said, of plasma,
and you use zap it with the laser and you
choose the laser frequency just right to excite oscillations in
the electrons in the plasma to create this wake field,
and then you dump your particle into it and it
sort of like surfs along this electromagnetic field that you've
created with your laser, and it gets shot at the end,
going much much faster. Interesting, all right, well, maybe take

(36:32):
a step a little bit of a step back here.
How does the laser cause the electrons to form into waves?
Like do electrons interact with photons? Is that the idea
electrons do interact with photons, and so lasers are just
like a great way to dump energy into the plasma.
And typically you can think about a plasma as like
a bunch of individual particles. You know, you have protons,

(36:53):
you have electrons that have charges, so they can interact
with photons and fields and all this stuff. But that's
a little bit of a nightmare because there're so many
of them. It just seems like a buzzing chaos. But
you can also think about the plasma sort of like
collectively and think about the collective motion of the electrons.
So plasmas have like tiny, little local behavior, but they
also have sort of like long distance collective behavior. You

(37:16):
can get plasmas to do things like have waves moving
through them, And so if you dump a laser beam
into it with the right frequency and you can sort
of excite it to do these waves the same way
you can if you like slap your hand against the
surface of a lake and do it at the right frequency,
you can get the lake to produce these waves. But
I guess the main mechanism is that it's interacting with

(37:37):
the electrons, because I guess light doesn't interact with the protons.
The light does interact with the protons as well, right,
protons are also charged, but remember protons are much more
massive than electrons, and so the same energy doesn't accelerate
those protons to move as much. So this whole thing
happens really really fast. Basically before the protons can sort
of get out of bed. The electrons have this big

(37:58):
wave that passes through them, and the protons are like
what sort of like me? And in this podcast right now?
All right, well, let's let's react to that laser a
bit of knowledge there, and let's dig a little bit
more into this effect than how you can use it
to axillary particles, maybe faster than the Large Hadron collider.
But first let's take another quick break. All right, we're

(38:29):
talking about a new way to killary particles that is
maybe faster and cheaper and better than the current technology
which is at the Large Hadron Collider. And so this
technology involves using a plasma. So you have a plasma,
which is like a gas where all of the atoms
have been broken down into single electrons and maybe protons

(38:51):
or at least clumps of protons, and so you have
the soup of all this stuff floating around that has
a charge, and then you shoot a laser into it.
And somehow that laser cites things, or maybe it causes
electrons to clump or to scatter. What exactly is happening there.
It causes the electrons to wiggle, It creates like a
wave of the electrons moving through the plasma, and again

(39:12):
you choose it very specifically the laser pulsed length to
be resonant with the modes of the plasma. Everything that
can wiggle, everything we can describe in terms of like
wave physics has resonant frequencies, the way, for example, your
shower is really good and amplifying certain frequencies when you're
singing and not others, or guitar strings like to oscillate
at certain frequencies and not others. They're resonant frequencies in

(39:36):
the same way that like a laser is made use
a resonant cavity. And so the equations of the motion
of the electrons who the plasma allow for certain frequencies
of collective motion where the electrons will like slash back
and forth all together. Instead of getting like a bunch
of individual electrons doing their own thing, you get this
like collective behavior of all the electrons if you push

(39:57):
it the right way, sort of like pushing your kid
on a swing right shit the right frequency, and your
kids can get going really really fast. You push it
like random times, then you're going to get like chaotic
motion in the swing. And I guess that's what the
light is doing. Like the full time will hit electrons
in a certain way, and because of the frequency, does
it in different ways in different locations. And that's how

(40:17):
you create the wave inside of the plasma exactly. And
so in order to do this you need laser pulses.
You're not just like shining a bright laser beam into
this thing and heating up all the electrons. You're doing
laser pulses so that you have like laser pulses at
different locations through the plasma at the same time. So
those pulse lengths and the pulse timings have to be
just right to excite this motion in the plasma, like

(40:40):
push on the right electrons at the right moment across
the plasma to get this thing going. I guess it's
sort of like you said, it's like having a pool
and then you have kind of like a wave maker
in the backack, like one of those pool and those
water parks. Right, You're like you're using the laser to
create waves in the pool, and then you're sort of
dropping like a little kid in the life preserver. Hey,
we'll get pushed by the waves to the shallow end.

(41:02):
That's kind of the idea, right, that's the idea. And
the reason this works better than the previous approach of
just having like two metal plates and an electric field
across them is because you can have much much stronger
electric fields in a plasma without anything breaking down. Basically,
the plasma is already broken down, right, there's nothing else
to break down, so, like there's no limit to how

(41:23):
much you can bunch electrons together or something within a
plasma or there maybe the kind is right is in there,
Like you can't bunch electrons infinitely. You can't bunch it infinitely,
but you can dump a lot of energy into this plasma.
And the cool thing is your laser beam doesn't have
to have as much energy sort of per photon. You
can just do a lot of photons to end up
with a lot of energy. So you don't need to

(41:44):
already have a super high energy laser to create a
super high energy particle beam. You can use a high
intensity laser to dump a lot of energy into the
plasma which creates these fields, and then accelerate the particles
to very high energy. Now, which particles are you accelerating
then the electrons in the plasma or the protons in

(42:04):
the plasma or are you trying to accelerate something else? Neither, right,
So then you dump in a particle bunch that you're
trying to accelerate, and they move through the plasma following
this wake, following the wake of these electrons, and they're
sort of like the surfers. Wouldn't you be accelerating protons too?
Aren't protonons part of the soup? Like how do you
you know, like if you have a soup with a wave,
they sort of like in our pool analogy, or you

(42:26):
have a WaveMaker in the back and you're trying to
accelerate a drop of water you dump into it. So
the protons in the plasma don't get accelerated because they
don't respond on this time scale. The whole thing happens
like too fast for them to even get moving. The
electrons in the plasma they do get excited, and you
do get this wave through the plasma, and then you
have a third bunch which sort of rides that electric wave.

(42:47):
The wake of that electron wave is a very high
gradient electric field which you will accelerate a particle that's
put in just the right location and velocity the same
way as surfer needs to catch a wave to ride it,
they need to be in the right spot and already
going at the right speed. That's why the surfer rides
the wave. But the other things are left behind. And

(43:09):
so you have this like third group which rides that wake,
sort of like the surfer on the wave right, right,
but except that the surfer is made out of water too. Yes,
in this case, the surfer is made out of matter.
The waves are made out of matter, right. It's just
a question of where you are and how fast you're
already going. And so if you're in the right location,
if it's timed just right, then you're riding that wave

(43:31):
and you're constantly getting accelerated, whereas electrons in these waves
are sort of slashing back and forth. I guess maybe
what's confusing me is that I feel like if you
drop a bunch of electrons into an electron soup, they'll
just get, you know, absorbed by the soup. You know.
But maybe the right way to think about it is
more like you have this wave pool. You're making the waves,
and then you shoot. There's a jet of water in

(43:54):
the back that's shooting it towards the shallow end, and
somehow it kind of gets an extra busive speed by
the waves. If you just dropped electrons into any random
spot in the plasma, they would become part of the plasma.
But if you set up this wave and then inject
particles at the right place with the right speed, they
can ride the wave generated by the plasma without becoming

(44:16):
part of the plasma. All right, that's the technology. It's
using plasma. But plasma is kind of tricky, right, Plasma
is super duper hot and it's really hard to contain,
and you also need maggots to contain plasma. So how
well does this technology work? Well, it works really really
well so far. It's taken decades. Like the original ideas
are from like the fifties, and then in the seventies

(44:37):
people started working in the first prototypes. It was actually
here at you see Irvine and a guy named Norm
Rustoker who pioneered this technology together with his grand student
Toshiki Tajima. But they were limited by the laser technology.
You need like really really fast pulses. And then in
the nineties people developed like super ultra fast sync lasers
and that's when the first demonstration was performed. But by

(44:59):
now people have been doing it all over the world,
and they've been able to create these little accelerators that
can accelerate particles to very high speeds over short distances.
And we typically measure this in terms of like how
much energy can you dump into a particle per centimeter, right,
because you want to accelerate a particle and you don't
want to have to take a mile or two miles
to do it. And so these little plasma accelerators have

(45:22):
been able to accelerate particles too much higher energies per
centimeter than the traditional approach, by a factor of a
hundred or a thousand. Cool. But I guess you know,
how are they overcoming the difficulties in the problem? Right?
Like how do you first of all maintain a plasma
that's pretty hard, and then how do you shoot electrons
into it? And how do you get them out of
the plasma. So maintaining a plasma is not always that hard, right,

(45:45):
Like you have plasma in the fluorescent lights that are
above you, or it's just very dilute and so it
doesn't like destroy the glass. And you typically think about
plasmas being really hard to contain in the case of
like fusion experiments, when you need a certain density also
in order to act fusion. We don't want fusion happening
in these plasmas, so they don't have to be actually
that dense. So the containment is not nearly as challenging

(46:07):
as it is in the case of fusion experiments. You
can just basically have a can of the plasma and
it's all right, and that's enough to get particles going.
That's enough to get particles going. The main challenge was
really the lasers, and now they've solved that, and so
now they've really demonstrated this. They have these devices that
it can actually accelerate particles to tens of GeV over
centimeters or tens of centimeters, which is very exciting. It's

(46:31):
exciting because it's a small amount. But you're also you're
thinking ahead and you're thinking, we're going to stack these
up to get like a thousand of these to get
a terra electronvol exactly. So now the question is can
they scale Where they've done it is they've proven the
principle that you can accelerate particles more effectively over short distances.
But we're not that interested in tiny little accelerators. We

(46:52):
still want them kind of big so we can get
to really high energies. And so the question is can
you stack these things up? And that's where the technology
struggle is right now, because what you need to do
is like match these things up. You need to keep
these things in sync. When you have the particles that
you're accelerating come out of one stage of a plasma
accelerator and you want to send them into the next one,
then you have to like time the laser pulses in

(47:14):
that next plasma accelerator perfectly, so like your little bunch
of accelerating particles hit just the right part of the wave,
otherwise everything's lost. And in order to get that all
that timing just perfectly in sync is very very challenging.
So what they've been able to do is match a
couple of stages, maybe up to like five stages, but
nobody's confident that they can do it for like a

(47:35):
hundred or a thousand, which is the kind of thing
you would need to do to really get to like
physics level accelerators where we can start answering deep questions
about the universe. So we're maybe still kind of far
away because you would need to be able to sink
and stack you're like, you're saying hundreds of these in
a row or maybe one in a circle. Is the
idea to put them all in a row and for

(47:57):
a straight accelerator or to maybe replace its lerators at
the LC. It depends on what you want to accelerate.
For electrons, you can't really accelerate them in the circle
because when you bend electrons in a circle, they radiate
away photons and they'll lose their energy really really fast. Protons, however,
you can accelerate them in a circle, and because they
have more masks, they tend to radiate less. So that's

(48:18):
why protons accelerators tend to be circles and electron accelerators
tend to be straight lines. So people want to do both.
They want to do straight electron accelerators and then want
to occur protons into circles to smash them together. Protons
we can tend to get to higher energies because of
these circular colliders. I think this technology has come a
long way in the last few decades. It's definitely not
ready for prime time. Nobody's like proposing, let's build one

(48:40):
of these things in five years or in ten years.
But there are like larger and larger demonstration experiments being
built and that are working, and lots of different ideas
that people are using to develop these things, not just
laser pulses, is ones where you drive it with a
proton beam, and all sorts of other variations. It's a
very exciting area and it might be in like you know,

(49:00):
a couple of decades that we're ready to talk about,
like building a LHC size or super LT size particle
accelerator that's significantly smaller than the other plans we have.
So this technology will also accilerate protons. It can also
accelerate protons, yes, but then I guess you'll run into
the same problem that you haven't in the LHC, Like
if you can make them go faster, but then you

(49:22):
still need to man to bend them into a circle
or you need to build a bigger circle. Yeah, you'll
still have that problem if you want to bend into
a circle. But if you have a super duper plasma accelerator,
maybe you just get them up to super high speeds
in a straight line, which could also work for protons.
I mean, if it's powerful enough, then you don't need
to go around many many times interesting. Well, there's a
lot of promise there. It sounds like it's definitely something

(49:43):
people are hoping is around the corner, and that might
revolutionize the way we're doing particle physics, because the way
we're doing it right now definitely doesn't seem sustainable. I mean,
particle physicists are talking about the next generation of colliders
and how it's going to cost one hundred billion dollars
and I'm all for it, you know, of course, but
I'm pretty skeptical that governments are going to pony up
that much money for another experiment. And so I'm looking

(50:05):
forward to, you know, the revolution that makes particle physics cheaper,
faster better. Did I tell you every once went to
a conference for this technology? No you didn't. Did it
accelerate your mind? Yeah? I got smashed. My brain got
smashed a thousand tiny bits. All right. Well, there's a
lot of promise in this new way of accelerating things,
but it also sounds like there's a ton of challenges

(50:27):
because you still have to scale these up, and you
still have to maybe potentially bend them into a circle.
Which city should we build the next giant particle collider
on the Pasadena. Oh good, good, not South Pasadena exactly,
always your neighbors. All right, Well, hopefully that made you
think a little bit about how scientists are out there
trying to break things apart and trying to uncover what's

(50:48):
inside of the fundamental particles that make up nature and
matter itself. That's right, because to answer the deepest questions
in the universe, we need to develop more and more technology.
We need better, inc more clever engineers to give us
the tools we can use to ask these questions. And
maybe it's gonna be plasma technology, or maybe it's gonna
be something totally different that somebody else out there sinks up.

(51:11):
We need more money or cheaper physicists, one of the two,
but the skip fund the engineers. All right, Well, we
hope you enjoyed that. Thanks for joining us, See you
next time. Thanks for listening, and remember that Daniel and
Jorge Explain the Universe is a production of iHeartRadio. For

(51:34):
more podcasts from iHeartRadio, visit the iHeartRadio app, Apple Podcasts,
or wherever you listen to your favorite shows.