Summary on plasma wave emissions observed by JIKIKEN

The important wave phenomena observed by current observations of JIKIKEN are as follows: i) Auroral kilometric radio waves; ii) Upper hybrid mode emissions; iii) (n + 1/2) fc emissions; iv) Principal phenomena of VLF frequency range such as whistler, chorus, and hiss; v) Pure-tone emissions in VLF range; vi) Artificially stimulated plasma waves and observation of plasma parameters; vii) Planetary radio waves; viii) Solar type III out burst. As a preliminary approach to verify the wave particle interaction processes, investigations of the energy spectra have also been made for the case of the UHR mode plasma wave and pure-tone emission in ELF and VLF ranges. Very long lasting UHR resonance has been triggered by 500 μsec pulse in the stimulated plasma wave experiment. The resonance persists up to 125 msec even in VLF range (below 30 KHz) and the electron cyclotron resonances are stimulated in very high harmonics number n; in the maximum case, sometimes, n = 20. Using these resonance frequencies, the plasmapause electron density distributions are obtained. (author)