Scaled Experiment to Investigate Auroral Kilometric Radiation Mechanisms in the Presence of Background Electrons

S. L. McConville*, K. Ronald, D. C. Speirs, K. M. Gillespie, A. D. R. Phelps, A. W. Cross, R. Bingham, C. W. Robertson, C. G. Whyte, W. He, M. King, R. Bryson, I. Vorgul, R. A. Cairns, B. J. Kellett

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

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Abstract

Auroral Kilometric Radiation (AKR) emissions occur at frequencies similar to 300kHz polarised in the X-mode with efficiencies similar to 1-2% [1,2] in the auroral density cavity in the polar regions of the Earth's magnetosphere, a region of low density plasma similar to 3200km above the Earth's surface, where electrons are accelerated down towards the Earth whilst undergoing magnetic compression. As a result of this magnetic compression the electrons acquire a horseshoe distribution function in velocity space. Previous theoretical studies have predicted that this distribution is capable of driving the cyclotron maser instability. To test this theory a scaled laboratory experiment was constructed to replicate this phenomenon in a controlled environment, [3-5] whilst 2D and 3D simulations are also being conducted to predict the experimental radiation power and mode, [6-9]. The experiment operates in the microwave frequency regime and incorporates a region of increasing magnetic field as found at the Earth's pole using magnet solenoids to encase the cylindrical interaction waveguide through which an initially rectilinear electron beam (12A) was accelerated by a 75keV pulse. Experimental results showed evidence of the formation of the horseshoe distribution function. The radiation was produced in the near cut-off TE01 mode, comparable with X-mode characteristics, at 4.42GHz. Peak microwave output power was measured similar to 35kW and peak efficiency of emission similar to 2%, [3]. A Penning trap was constructed and inserted into the interaction waveguide to enable generation of a background plasma which would lead to closer comparisons with the magnetospheric conditions. Initial design and measurements are presented showing the principle features of the new geometry.

Original languageEnglish
Title of host publication15th International Congress on Plasma Physics (ICPP2010) & 13th Latin American Workshop on Plasma Physics (LAWPP2010)
Place of PublicationBristol
PublisherIOP Publishing Ltd.
Number of pages6
DOIs
Publication statusPublished - 7 May 2014
Event15th International Congress on Plasma Physics (ICPP) / 13th Latin American Workshop on Plasma Physics (LAWPP) - Santiago, Chile
Duration: 8 Aug 201013 Aug 2010

Publication series

NameJournal of Physics Conference Series
PublisherIOP PUBLISHING LTD
Volume511
ISSN (Print)1742-6588

Conference

Conference15th International Congress on Plasma Physics (ICPP) / 13th Latin American Workshop on Plasma Physics (LAWPP)
Country/TerritoryChile
Period8/08/1013/08/10

Keywords

  • Cyclotron maser radiation
  • Laboratory plasmas
  • Space
  • Distributions
  • Generation

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