A Laboratory Study of Ion Energization by EIC (Electrostatic Ion Cyclotron) Waves and Subsequent Upstreaming along Diverging Magnetic Field Lines,
IOWA UNIV IOWA CITY DEPT OF PHYSICS AND ASTRONOMY
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A laboratory study related to energetic upstreaming ions in the ionosphere-magnetosphere system is described. The experiment was carried out in a cesium Q machine plasma with a region of nonuniform magnetic field. Electrostatic ion cyclotron waves were excited by drawing an electron current to a small biased exciter electrode. In the presence of the instability, ions are heated in the direction perpendicular to B. Using a gridded retarding potential ion energy analyzer, we followed the evolution of the ion velocity distribution as the ions passed through the heating region and subsequently flowed out along the diverging B field lines. As expected, the heated ions transfer their energy from perpendicular to parallel motion as they move through the region or diverging B field. Both their parallel thermal energy and the parallel drift energy increase at the expense of the perpendicular energy.
- Atmospheric Physics