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Dudnikova, G.

Paper Title Page
THPEC073 RF H- Ion Source with Saddle Antenna 4226
 
  • V.G. Dudnikov, R.P. Johnson
    Muons, Inc, Batavia
  • G. Dudnikova
    UMD, College Park, Maryland
  • M.P. Stockli, R.F. Welton
    ORNL, Oak Ridge, Tennessee
  
 

In this project we are developing an RF H- surface plasma source which will synthesize the most important developments in the field of negative ion sources to provide high pulsed and average current, high brightness, good lifetime, high reliability, and higher power efficiency. We describe two planned modifications to the present SNS external antenna source in order to increase the plasma density near the output aperture: 1) replacing the present 2 MHz plasma-forming solenoid antenna with a 13 MHz saddle-type antenna and 2) replacing the permanent multicusp magnetic system with a weaker electro-magnet. Progress of this development will be presented.

  
THPD072 Laser Energy Conversion to Solitons and Monoenergetic Protons in Near-critical Hydrogen Plasma 4446
 
  • I. Pogorelsky, M. Babzien, M.N. Polyanskiy, V. Yakimenko
    BNL, Upton, Long Island, New York
  • N. Dover, Z. Najmudin, C.A.J. Palmer, J. Schreiber
    Imperial College of Science and Technology, Department of Physics, London
  • G. Dudnikova
    UMD, College Park, Maryland
  • M. Ispiryan, P. Shkolnikov
    Stony Brook University, StonyBrook
  
 

Recent theoretical and experimental studies point to better efficiency of laser-driven ion acceleration when approaching the critical plasma density regime. Simultaneously, this is the condition for observing solitons: "bubble"-like quasi-stationary plasma formations with laser radiation trapped inside. Exploring this regime with ultra-intense solid state lasers is problematic due to the lack of plasma sources and imaging methods at ~1021/cc electron density. The terawatt picosecond CO2 laser operated at Brookhaven's Accelerator Test Facility offers a solution to this problem. At 10 μm laser wavelength, the CO2 laser shifts the critical plasma density to 1019/cc which is attainable with gas jets and can be optically probed with visible light. Capitalizing on this approach, we focused a circular-polarized CO2 laser beam with a0=0.5 onto a hydrogen gas jet and observed monoenergetic proton beams in the 1 MeV range. Simultaneously, the laser/plasma interaction region has been optically probed with a 2nd harmonic picosecond Nd:YAG laser to reveal stationary soliton-like plasma formations. 2D PIC simulations agree with experimental results and aid in their interpretation.