Plasma-Based Particle Accelerators: There's Plenty of Room at the Bottom

Event Dates: 

Wednesday, February 4, 2015 - 4:00pm

CTQM Seminar Type: 

  • Related Seminar Series

Speaker Name(s): 

Mike Downer

Speaker Affiliation(s): 

University of Texas, Austin

Abstract, Event Details: 

Over the past few years, compact plasma-based particle accelerators have advanced sufficiently that it is no longer a pipe dream* to imagine a tabletop x-ray free-electron laser in every major university in the world [1], or proton cancer therapy on a scale that many hospitals could afford.  I will survey recent experimental highlights in the field that make these hopes more realistic than even a few years ago.  These include a milestone achieved recently using the Texas Petawatt Laser:  nearly mono-energetic acceleration of plasma electrons to 2 GeV with unprecedented sub-milliradian beam divergence [2].  I will discuss near-term prospects for improving plasma-based accelerators further, and for obtaining tunable x-ray radation from them [3].   Finally I will describe new holographic techniques that enable experimenters to visualize the electron density waves that lie at the heart of plasma-based accelerators [4-6].  Such 4D visualization, previously available only from intensive computer simulations, helps physicists understand how plasma-based particle accelerators work, and how to make them work better.

*Oxford English Dictionary: “ an unrealistic or fanciful hope or scheme; with reference to the kind of visions experienced when smoking an opium pipe”
[1] K. Nakajima, “Towards a table-top free electron laser,” Nature Physics 4, 92 (2008).
[2] X. Wang et al., “Quasi-monoenergetic laser-plasma acceleration of electrons to 2 GeV,” Nature Communications 4, 1988 (2013). 
[3] H. E. Tsai  et al., “Compact tunable Compton x-ray source from laser-plasma accelerator and plasma mirror,” Phys. Plasmas, in press (2015). 
[4] N. H. Matlis et al., “Snapshots of laser wakefields,” Nature Physics 2, 749 (2006).
[5] Z. Li et al., “Single-shot tomographic movies of light-velocity objects,” Nature Communications 5, 3085 (2014). 
[6] Z. Li et al., “Single-shot visualization of evolving laser wakefields using an all-optical streak camera,” Phys. Rev. Lett., in press (2014).