Variation of Langmuir wave polarization with electron beam speed in type III radio bursts

Journal Article · Thu Jun 13 04:00:00 EDT 2013 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.4811030· OSTI ID:22118612

Malaspina, David M. ^[1]; Cairns, Iver H. ^[2]; Ergun, Robert E. ^[3]

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1. Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303 (United States)
2. School of Physics, University of Sydney, New South Wales 2006 (Australia)
3. Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303 (United States) and Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80303 (United States)

Observations by the twin STEREO spacecraft of in-situ electric field waveforms and radio signatures associated with type III radio bursts have demonstrated that the polarization of electron beam-driven waves near the local plasma frequency depends strongly on the speed of the driving electron beam. We expand upon a previous study by including all radio bursts with in-situ waveforms observed by STEREO in 2011. The expanded data set contains five times more radio bursts (35 up from 7) and three times as many Langmuir waves (663 up from 168). While this expanded study supports the results of the original study, that faster (slower) beam electrons drive waves with strong (weak) electric fields perpendicular to the local magnetic field, the larger data set emphasizes that the observation of strong perpendicular electric fields at high electron beam speeds is probabilistic rather than definite. This property supports the interpretation of wave polarization dependence on beam speed as Langmuir/z-mode waves shifted to small wave number through interaction with turbulent solar wind density fluctuations.

• OSTI ID: 22118612
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 1539; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ASTROPHYSICS
DENSITY
ELECTRIC FIELDS
ELECTRON BEAMS
FLUCTUATIONS
INTERPLANETARY MAGNETIC FIELDS
LANGMUIR FREQUENCY
MAGNETISM
PLASMA
PLASMA INSTABILITY
POLARIZATION
SOLAR ELECTRONS
SOLAR RADIO BURSTS
SOLAR RADIOWAVE RADIATION
SOLAR WIND
VELOCITY
WAVE FORMS