Auroral Kilometric Radiation -- the Electron Cyclotron Maser Paradigm

Auroral kilometric radiation (AKR) is the paradigm of intense radio emission from planetary magnetospheres. Being close to electron gyro frequency and/or its lower harmonics, observation indicates non-thermal state source plasma. Emission produced when plasma enters a energetic excitation which results in deformation distribution function. Under certain conditions this leads "quasi-coherent" emission. It believed that weakly-relativistic electron-cyclotron-maser instability responsible for kind radiation. Since energetically normally not {primary} importance large-scale magnetospheric phenomena, AKR as such has, purposes physics, become considered marginal problem. Here notion questioned. while applying auroral region mainly during magnetospherically disturbed times {carries just fraction total substorm energy. is, however, diagnostic power physics upper ionosphere and Space Weather research}. As fundamental physical problem generation plasmas {it remains resolved yet. Many questions have been left open even dealing only with electron-cyclotron-maser. These can advantageously be studied magnetosphere proper both by theory, continuously accessible place space. The most important are listet here hint on how they should attacked. Its value sought role it play application other magnetized planets, extra-solar strongly astronomical objects} an {tool diagnose matter range beyond thermal, shock or synchrotron