New Evidence for Third Harmonic Radiation in Interplanetary Type III Solar Radio Bursts
Abstract
We present new direct evidence for third harmonic components in the electromagnetic radiation generated in interplanetary type III solar radio emissions observed locally near 1 AU by the Wind spacecraft. This new evidence comes from our multifaceted analyses, at high-time and -frequency resolution, of the type III associated local radio emissions that are occasionally generated in the vicinity of the Wind spacecraft. The plasma density at the spacecraft and associated Langmuir waves and energetic electron beams, as well as simultaneous observations from the STEREO spacecraft where possible, are used to confirm the local nature of the observed radiation. These analyses suggest that, in addition to the more common second harmonic component, a third harmonic component is sometimes clearly evident in the local type III radiation detected near 1 AU. Detailed analyses for several selected events that we believe provide unambiguous evidence of third harmonic components in interplanetary type III bursts will be presented. We find that the third harmonic component is generally less intense than the second harmonic, but it can sometimes be equally intense. Sometimes the third harmonic component is expected, but it is not observed. These observations and analyses are potentially very relevant to the Parker Solar Probe Mission. On its journey to the vicinity of the Sun, the Parker Probe will likely often encounter in-situ type III electron beams, with possible associated Langmuir waves and/or locally generated radio emissions that may be distinguishable from the intense remote type III radio emissions, as is the case for Wind at 1 AU.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMSH51E2885R
- Keywords:
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- 2164 Solar wind plasma;
- INTERPLANETARY PHYSICSDE: 2169 Solar wind sources;
- INTERPLANETARY PHYSICSDE: 7509 Corona;
- SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMYDE: 7524 Magnetic fields;
- SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY