Author: Bingham, R.
Paper Title Page
WEPPD059 Proton Acceleration by a Relativistic Laser Frequency-Chirp Driven Plasma Snowplow 2654
  • A. A. Sahai, T.C. Katsouleas
    Duke ECE, Durham, North Carolina, USA
  • R. Bingham
    STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
  • W.B. Mori, A. Tableman, F.S. Tsung, M. Tzoufras
    UCLA, Los Angeles, California, USA
  Funding: NSF-PHY-0936278, NSF-PHY-0904039 and NSFPHY-0936266, US DOE DE-FC02-07ER41500 and DE-FG02-92ER40727, DOE Fusion Science Center through a University of Rochester Subcontract No. 415025-G.
We analyze the use of a relativistic laser pulse with a controlled frequency chirp incident on a rising plasma density gradient to drive an acceleration structure for proton and light ion acceleration. The Chirp Induced Transparency Acceleration (ChITA) scheme is described with an analytical model of the velocity of the snowplow at critical density on a pre-formed rising plasma density gradient that is driven by positive chirp in the frequency of a relativistic laser pulse. The velocity of the ChITA-snowplow is shown to depend upon rate of rise of the frequency of the relativistic laser pulse, the normalized magnetic vector potential of the laser pulse and the plasma density gradient scale-length. We observe using 1-D OSIRIS simulations the formation and forward propagation of ChITA-snowplow, being continuously pushed by the chirping laser at a velocity in accordance with the analytical results. The trace protons reflect off of this propagating snowplow structure and accelerate monoenergetically. The control over ChITA-snowplow velocity allows the tuning of accelerated proton energies.