Magnetic instability by the relativistic laser pulses in overdense plasmas

The magnetic instability driven by the relativistic electron stream generated by ultra-intense laser is investigated with the help of a two-dimensional particle-in-cell simulation, which includes the relativistic binary collision. The linear growth rate of the instability is also studied using the two-stream fluid model, which consists of a fast electron current and a return current. The growth rate is evaluated numerically from the linearized equations of the electron fluids with the Maxwell equations. The kinetic effects of electrons on the magnetic instability are found to reduce the growth rate. The growth rate is maximum at the wavelength near the plasma skin length because of the plasma kinetic effect. When the initial plasma temperature is high, the growth rates of shorter wavelengths are significantly reduced. In the collisional plasma, the growth rates of modes whose wavelength is shorter than the plasma skin length are suppressed and the spectral peak of the growth rate shifts to long wavelength...