An Experimental Investigation of the Auroral Kilometric Radiation Emission Mechanism

Summary form only given. In this presentation we discuss a laboratory experiment for the investigation of instabilities associated with an electron beam subject to a magnetic compression of up to a factor of 30. Experimental results will be presented showing emission at a frequency of 11.7 GHz, corresponding to the relativistic cyclotron frequency, from a 42 keV electron beam subject to magnetic compression ratios in the range of 10 to 30. In addition, data from particle-in-cell code simulations will be presented showing the instability growth and saturation in an experimentally consistent geometry. A scenario analogous to this occurs in the terrestrial auroral zone, where particles are accelerated into the polar regions of the Earth´s magnetic dipole. The resultant horseshoe shaped velocity distribution has been shown to be unstable to a cyclotron-maser type instability. This instability has been postulated as being responsible for the auroral kilometric radiation and also nonthermal radiation from other astrophysical objects including stars with a suitable magnetic field configuration