Electron-beam-induced radio emission from ultracool dwarfs

S. Yu, J. G. Doyle, A. Kuznetsov, G. Hallinan, A. Antonova, A. L. MacKinnon, A. Golden

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

We present the numerical simulations for an electron-beam-driven and loss-cone-driven electron-cyclotron maser (ECM) with different plasma parameters and different magnetic field strengths for a relatively small region and short timescale in an attempt to interpret the recent discovered intense radio emission from ultracool dwarfs. We find that a large amount of electromagnetic (EM) field energy can be effectively released from the beam-driven ECM, which rapidly heats the surrounding plasma. A rapidly developed high-energy tail of electrons in velocity space (resulting from the heating process of the ECM) may produce the radio continuum depending on the initial strength of the external magnetic field and the electron beam current. Both significant linear polarization and circular polarization of EM waves can be obtained from the simulations. The spectral energy distributions of the simulated radio waves show that harmonics may appear from 10 to 70νpepe is the electron plasma frequency) in the non-relativistic case and from 10 to 600νpe in the relativistic case, which makes it difficult to find the fundamental cyclotron frequency in the observed radio frequencies. A wide frequency band should therefore be covered by future radio observations.

Original languageEnglish (US)
Article number60
JournalAstrophysical Journal
Volume752
Issue number1
DOIs
StatePublished - Jun 10 2012

Fingerprint

radio emission
masers
electron beams
radio
cyclotrons
electron
electrons
radio observation
plasma
radio waves
cyclotron frequency
plasma frequencies
electron plasma
circular polarization
spectral energy distribution
linear polarization
beam currents
magnetic fields
polarization
field strength

Keywords

  • brown dwarfs
  • magnetic fields
  • masers
  • polarization
  • radio continuum: stars
  • stars: low-mass

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Yu, S., Doyle, J. G., Kuznetsov, A., Hallinan, G., Antonova, A., MacKinnon, A. L., & Golden, A. (2012). Electron-beam-induced radio emission from ultracool dwarfs. Astrophysical Journal, 752(1), [60]. https://doi.org/10.1088/0004-637X/752/1/60

Electron-beam-induced radio emission from ultracool dwarfs. / Yu, S.; Doyle, J. G.; Kuznetsov, A.; Hallinan, G.; Antonova, A.; MacKinnon, A. L.; Golden, A.

In: Astrophysical Journal, Vol. 752, No. 1, 60, 10.06.2012.

Research output: Contribution to journalArticle

Yu, S, Doyle, JG, Kuznetsov, A, Hallinan, G, Antonova, A, MacKinnon, AL & Golden, A 2012, 'Electron-beam-induced radio emission from ultracool dwarfs', Astrophysical Journal, vol. 752, no. 1, 60. https://doi.org/10.1088/0004-637X/752/1/60
Yu S, Doyle JG, Kuznetsov A, Hallinan G, Antonova A, MacKinnon AL et al. Electron-beam-induced radio emission from ultracool dwarfs. Astrophysical Journal. 2012 Jun 10;752(1). 60. https://doi.org/10.1088/0004-637X/752/1/60
Yu, S. ; Doyle, J. G. ; Kuznetsov, A. ; Hallinan, G. ; Antonova, A. ; MacKinnon, A. L. ; Golden, A. / Electron-beam-induced radio emission from ultracool dwarfs. In: Astrophysical Journal. 2012 ; Vol. 752, No. 1.
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