Electromagnetic pulse amplification in a magnetized nearly stable plasma layer
By combining the analytical approach and the test particle simulation, we examine the possibility of strong amplification of appropriate weak electromagnetic pulse in a magnetized plasma layer. Amplification occurs with the rate of instability of the hydrodynamic type through the beam plasma amplifier mechanism (BPA). This mechanism provide the excitation of intense rapidly changing radiation at an extraordinary plasma mode without a significant anisotropy of the distribution function. In a plasma with an nearly stable distribution of particles in the velocity space, the gain of radiation is determined by the plasma thermal to magnetic pressure ratio (β). Our simulations indicate the importance of the beam plasma amplifier mechanism for the interactions of active particle cloud with electromagnetic waves. Actually, a fraction of plasma shot noise can sharply amplify and turn into intense rapidly changing discrete emissions. Discrete emissions can be excited both in laboratory plasma installations and in the form of VLF chorus in the Earth's magnetosphere.