PARAMETRIC RESONANT ACCELERATION OF PARTICLES BY GRAVITATIONAL-WAVES

We study the resonant interaction of charged particles with a gravitat ional wave propagating in the non-empty interstellar space in the pres ence of a uniform magnetic field. It is found that this interaction ca n be cast in the form of a parametric resonance problem which, besides the main resonance, allows for the existence of many secondary ones. Each of them is associated with a non-zero resonant width, depending o n the amplitude of the wave and the energy density of the interstellar plasma. Numerical estimates of the particles' energization and the en suing damping of the wave are given.