Laboratory investigation of cyclotron emission processes for auroral radiation

A.D.R. Phelps, K. Ronald, David Speirs, S.L. McConville, A.W. Cross, I. Vorgul, C.W. Robertson, R. Bingham, R.A. Cairns, C.G. Whyte, B.J. Kellett

Research output: Contribution to journalConference Contribution

Abstract

When a beam of electrons encounters an increasing magnetic field along its vector of motion, conservation of the magnetic moment results in the formation of a crescent or horseshoe shaped velocity distribution. 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 and expand adiabatically in velocity space. The resultant horseshoe shaped velocity distribution has been shown to be unstable with respect to a cyclotron-maser type instability. This instability has been postulated as the mechanism responsible for auroral kilometric radiation and thermal radiation from other astrophysical bodies. In this paper we present the results of recent numerical simulations and laboratory investigations of radiation emissions from electron beam which have been subject to magnetic compression. Electron beam diagnostics demonstrated the formation of the desired velocity distribution. Radiation was generated at both 11.7GHz and 4.45GHz by an electron beam of current 5-25A and energy 75kV subject to magnetic compression ration of up to 30. Conversion efficiencies between beam and radiation power were achieved of up to 2.5% and strong agreement was achieved between the numerical investigations and the experimental measurements.
Original languageEnglish
JournalGeophysical Research Abstracts
Volume8
Issue number05904
Publication statusPublished - 2006
Event3rd European Geosciences Union General Assembly - Vienna, Austria
Duration: 2 Apr 20067 Apr 2006

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cyclotrons
magnetic compression
radiation
velocity distribution
electron beams
auroral zones
rations
thermal radiation
masers
magnetic dipoles
encounters
polar regions
conservation
astrophysics
electrons
magnetic moments
magnetic fields
simulation

Keywords

  • auroral masers
  • radiation
  • plasmas
  • physics

Cite this

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title = "Laboratory investigation of cyclotron emission processes for auroral radiation",
abstract = "When a beam of electrons encounters an increasing magnetic field along its vector of motion, conservation of the magnetic moment results in the formation of a crescent or horseshoe shaped velocity distribution. 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 and expand adiabatically in velocity space. The resultant horseshoe shaped velocity distribution has been shown to be unstable with respect to a cyclotron-maser type instability. This instability has been postulated as the mechanism responsible for auroral kilometric radiation and thermal radiation from other astrophysical bodies. In this paper we present the results of recent numerical simulations and laboratory investigations of radiation emissions from electron beam which have been subject to magnetic compression. Electron beam diagnostics demonstrated the formation of the desired velocity distribution. Radiation was generated at both 11.7GHz and 4.45GHz by an electron beam of current 5-25A and energy 75kV subject to magnetic compression ration of up to 30. Conversion efficiencies between beam and radiation power were achieved of up to 2.5{\%} and strong agreement was achieved between the numerical investigations and the experimental measurements.",
keywords = "auroral masers, radiation, plasmas, physics",
author = "A.D.R. Phelps and K. Ronald and David Speirs and S.L. McConville and A.W. Cross and I. Vorgul and C.W. Robertson and R. Bingham and R.A. Cairns and C.G. Whyte and B.J. Kellett",
year = "2006",
language = "English",
volume = "8",
journal = "Geophysical Research Abstracts",
issn = "1029-7006",
number = "05904",

}

Laboratory investigation of cyclotron emission processes for auroral radiation. / Phelps, A.D.R.; Ronald, K.; Speirs, David; McConville, S.L.; Cross, A.W.; Vorgul, I.; Robertson, C.W.; Bingham, R.; Cairns, R.A.; Whyte, C.G.; Kellett, B.J.

In: Geophysical Research Abstracts, Vol. 8, No. 05904, 2006.

Research output: Contribution to journalConference Contribution

TY - JOUR

T1 - Laboratory investigation of cyclotron emission processes for auroral radiation

AU - Phelps, A.D.R.

AU - Ronald, K.

AU - Speirs, David

AU - McConville, S.L.

AU - Cross, A.W.

AU - Vorgul, I.

AU - Robertson, C.W.

AU - Bingham, R.

AU - Cairns, R.A.

AU - Whyte, C.G.

AU - Kellett, B.J.

PY - 2006

Y1 - 2006

N2 - When a beam of electrons encounters an increasing magnetic field along its vector of motion, conservation of the magnetic moment results in the formation of a crescent or horseshoe shaped velocity distribution. 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 and expand adiabatically in velocity space. The resultant horseshoe shaped velocity distribution has been shown to be unstable with respect to a cyclotron-maser type instability. This instability has been postulated as the mechanism responsible for auroral kilometric radiation and thermal radiation from other astrophysical bodies. In this paper we present the results of recent numerical simulations and laboratory investigations of radiation emissions from electron beam which have been subject to magnetic compression. Electron beam diagnostics demonstrated the formation of the desired velocity distribution. Radiation was generated at both 11.7GHz and 4.45GHz by an electron beam of current 5-25A and energy 75kV subject to magnetic compression ration of up to 30. Conversion efficiencies between beam and radiation power were achieved of up to 2.5% and strong agreement was achieved between the numerical investigations and the experimental measurements.

AB - When a beam of electrons encounters an increasing magnetic field along its vector of motion, conservation of the magnetic moment results in the formation of a crescent or horseshoe shaped velocity distribution. 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 and expand adiabatically in velocity space. The resultant horseshoe shaped velocity distribution has been shown to be unstable with respect to a cyclotron-maser type instability. This instability has been postulated as the mechanism responsible for auroral kilometric radiation and thermal radiation from other astrophysical bodies. In this paper we present the results of recent numerical simulations and laboratory investigations of radiation emissions from electron beam which have been subject to magnetic compression. Electron beam diagnostics demonstrated the formation of the desired velocity distribution. Radiation was generated at both 11.7GHz and 4.45GHz by an electron beam of current 5-25A and energy 75kV subject to magnetic compression ration of up to 30. Conversion efficiencies between beam and radiation power were achieved of up to 2.5% and strong agreement was achieved between the numerical investigations and the experimental measurements.

KW - auroral masers

KW - radiation

KW - plasmas

KW - physics

UR - http://www.cosis.net/abstracts/EGU06/05904/EGU06-J-05904.pdf

M3 - Conference Contribution

VL - 8

JO - Geophysical Research Abstracts

JF - Geophysical Research Abstracts

SN - 1029-7006

IS - 05904

ER -