LINEAR-CONVERSION THEORY OF ENERGETIC MINORITY-ION BERNSTEIN-WAVE PROPAGATION ACROSS GYRORESONANCE IN NONUNIFORM MAGNETIC-FIELD

An energetic minority-ion population, such as neonatal fusion alphas, can support a Bernstein wave whose frequency is a harmonic of their gy rofrequency. The sign of the wave energy depends on the local wave vec tor, whose rate of change is proportional to the magnetic-field gradie nt. As a result of the field nonuniformity, the wave crosses the gyror esonance layer and its energy flips sign. This results in energy trans fer to a gyroballistic mode (which exists only in the resonance layer) , with a conversion coefficient exactly equal to 2. (C) 1996 American Institute of Physics.