Plasma-Based Acceleration
 
  • Introduction to Plasma-Based Acceleration

Plasma-Based Acceleration is one of the most vigorously pursued advanced acceleration scheme at this time. A great number of laboratories and workshops all over the world have performed the exploration on this area during the last 30 years. Because the ultrahigh accelerating gradients it supports, plasma-based accelerators are thought to have the potential to challenge the energy frontier. On the recent AAC (Advanced Accelerator Concepts), more than 60% of the reports are relative to this exciting field.
      There are two major directions of plasma-based acceleration, named LWFA (Laser Wakefield Accelerators) and PWFA (Plasma Wakefield Accelerators) respectively. The difference between these two methods is the driven beam. If we use an ultrahigh and ultrashort laser pulse to form the accelerating field, it is called LWFA. And PWFA uses electron beam in stead of laser pulse.
      With the significant progress on the laser technology, especially with the application of CPA (Chirped Pulse Amplification), LWFA becomes one of the hottest topics among the big high energy physics laboratories. Three labs in USA, UK and France reported their amazing success in getting monoenergetic particles simultaneously at 2004. In the following years, more than 10 laboratories did experiments on this area. The most 2 successful experiments are performed by LBNL (USA) - Oxford U. (UK) collaboration and KEK (Japan) - CAEP (China) collaboration. The maximum energy is 1GeV and 0.84GeV respectively. In the near future, multi-GeV experiment will be performed in Mianyang (Sichuan Province, China) by KEK-CAEP collaboration.
       On the other hand, PWFA experiments also have exciting results during these years. Experimental research on PWFA has been going on at SLAC (Stanford Linear Accelerator Center), UCLA (University of California, Los Angles), USC (University of Southern California), ANL (Argonne National Lab), FNL (Fermi National Lab), KEK, and more recently at BNL (Brookhaven National Lab). In the experiment performed at Stanford in 2006, the energy gain of more than 42GeV is achieved in a plasma wakefield accelerator of 85cm length, driven by 42GeV electron beam at the SLAC. Most electrons of the beam lost their energy to the plasma wave, but some in the back of the same beam pulse are accelerated with a field of ~52GV m-1. It is believed that the great success of the experiment is an important step towards demonstrating the possibility of PWFA for high-energy physics applications.

 
  • What We Have Done and Going to Do

We have formed a laser-plasma accelerator group to take participation in this encouraging field. Under our effects, the collaboration between IHEP (Institute of High Energy Physics, China) and IOP (Institute of Physics, China) has been established. And the collaborations between IHEP and CAEP and between IHEP and KEK are also being established.

      With the help of IOP, we have done some basic study on the simulation of laser-plasma interaction. We used the program developed by IOP calculating the wakefield generation and the plasma density variation.

wake

 
Simulation Result by KLAP program (developed by IOP)
 

     As one of the most important plans of this year, we are trying to join the KEK-CAEP collaboration to take part in the multi-GeV experiment performed in Mianyang.


D.Z. Li , IHEP