Stanford Science Penpals
Featured Scientist:
Griffin G.
Graduate student in Applied Physics
Name: Griffin G.
Birthplace: Houston, Texas
Field of Study: Plasma Physics
Specific research interests: Laser particle acceleration from liquid jets
Favorite thing about science: I get to meet people from all over the world who are excited about the same things as I am, and together we solve problems that nobody has ever had to think about before!
Fun Facts: I’ve played the double bass for more than 10 years. Once I got to play a bass used to record the soundtrack for the original Star Wars movies!
Griffin's Science
“How can we use powerful lasers to both understand plasmas in space and help people on Earth?”
Physicists have come up with ways to make very, very powerful lasers that are much brighter than the laser pointers you might use to play with a pet. These lasers flash on and off very quickly - often in less than a millionth of a millionth of a second! This pulse of laser light may only contain about as much energy as a lightbulb burns in a second, and while that may not sound impressive, it means that the laser is delivering, for a brief instant, as much power as the entire United States consumes on average over a year! (Donna Strickland and Gerard Mourou shared the 2018 Nobel Prize in Physics for developing a method that helps us make these lasers.)
This video shows how scientists at SLAC National Accelerator Laboratory, the place where I work, used powerful lasers to learn more about the insides of planets like Jupiter and stars like the Sun without having to go to space to look!
Scientists can also use these plasmas to make beams of particles, especially protons! In my research group, we use a special device that takes hydrogen gas and makes it so cold that it turns into a liquid, which we spray out in a jet shaped like a flat sheet. Then, when the laser hits this jet, a beam of protons comes out moving very fast. (That’s what “Multi-MeV” means in the picture below.) We can use these protons for lots of things, but one exciting idea is to use them to help treat cancer, because these protons are good at damaging tumors without hurting people. Doctors already do this, but the way they usually make protons takes a very big, expensive machine. With laser-produced protons, we hope to make smaller, less-expensive machines that can fit in more hospitals and treat more people!
This picture shows what happens when we shoot one of our hydrogen jets with a high-power laser: a beam of protons traveling very quickly comes out the back!
This is a picture of part of the Texas Petawatt Laser, which was once the most powerful laser in the world!
When we shine these lasers onto different targets, they change the targets into a plasma almost instantly. (A plasma is like a gas, except with the small parts that make up the gas, the atoms, pulled apart into pieces called electrons and nuclei.) We focus our lasers to very small spots on the targets, which makes plasmas that are under very high pressure because the laser is squeezing them in such a small area. Scientists can study these plasmas with many different tools to learn about what the insides of planets like Jupiter and stars like the Sun might be like.
Click here to watch a video of the flat hydrogen jet target my research group has developed! The sheet you see here is thinner than a human hair, so to make this video we had to look through a microscope.
One last thing I want to tell you is that I am an experimental physicist, which means that I do these experiments myself (plus a team of other physicists and engineers!) Experimental physicists have to do a lot of different jobs, but I really like learning to do these different things. Depending on what I have to do each day, I may be setting up lasers in a laboratory, using special tools to build new equipment, coding to perform data analysis, or writing papers to tell other scientists what we have found. One of my favorite things about being a scientist is the way I can watch the things my team and I have built operate successfully to tell us something new about the universe.
What questions is Griffin asking?
Like all scientists, I have a lot of different questions that I want to answer. The good thing is that by answering some of these questions, I’ll have more tools that I can use to help me work on the others! Some of the most important questions for me right now are:
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How can we operate our hydrogen jet in ways that help us make even more protons, or protons with more energy?
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If we make beams of particles that aren’t protons, what could we use those to do?
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How can other tools, like x-ray lasers or new diagnostic instruments, help us understand how lasers interact with their targets?
Do you have any questions about lasers? Plasma physics? Being an experimental physicist? Ask me by clicking below!
The inside of the target chamber at the Matter in Extreme Conditions instrument at SLAC National Accelerator Laboratory, where I do some of my work!