Laser excitation of electrostatic eigenmode of a plasma in azimuthal magnetic field and electron acceleration

The localized electrostatic eigenmodes of a plasma with parabolic density profile in the presence of azimuthal magnetic field are investigated in the slab model by taking stepwise variations in plasma density and magnetic field. The mode amplitude is maximum where magnetic field is maximum. A mode can be resonant by beating two collinear lasers with frequency difference equal to the frequency of the eigenmode. Such a mode efficiently accelerates energetic electrons, executing bounce motion in the azimuthal field to high energies. At dimensionless mode plasma wave amplitude a(p)=e phi(p0)/m(0)c(2)=0.55, 10 keV electrons in a plasma of density n=10(17)/cm(3) can be accelerated to 30 MeV energy. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3422545]