Wave-particle interaction in the auroral ionosphere in LF and HF range

Plasma wave observations using the sounding rockets, S-310JA-11 and S-310JA-12 have disclosed the following new aspects of wave-particle interaction processes in the auroral ionosphere: 1) generation of intense Z-mode waves by auroral particles through the inverse Landau damping, 2) confirmation of the leaked components of auroral kilometric radiation, and 3) detection of naturally generated electrostatic electron cyclotron harmonic (ESCH) waves in the frequency range lower than the local electron cyclotron frequency. It is pointed out that Z-mode waves in the auroral region have a very important role because the waves are easily generated being coupled with the particle precipitation. The leaked component of AKR is an important manifestation of the mode conversion processes. The generation of ESCH waves are associated with the nonlinear wave-particle interaction. The newly detected ESCH wave phenomena correspond to n = 0 case of the fDn emissions. (author)