PLASMA EMISSION BY COUNTER-STREAMING ELECTRON BEAMS

Citation:
PLASMA EMISSION BY COUNTER-STREAMING ELECTRON BEAMS, Ziebell, Luiz F., Petruzzellis Larissa T., Yoon Peter H., Gaelzer Rudi, and Pavan Joel , The Astrophysical Journal, Volume 818, Issue 61, (2016)

Abstract:

The radiation emission mechanism responsible for both type-II and type-III solar radio bursts is commonly
accepted as plasma emission. Recently Ganse et al. suggested that type-II radio bursts may be enhanced when the electron foreshock geometry of a coronal mass ejection contains a double hump structure. They reasoned that the counter-streaming electron beams that exist between the double shocks may enhance the nonlinear coalescence interaction, thereby giving rise to more efficient generation of radiation. Ganse et al. employed a particle-in-cell simulation to study such a scenario. The present paper revisits the same problem with EM weak turbulence theory, and show that the fundamental (F) emission is not greatly affected by the presence of counter-streaming beams, but the harmonic (H) emission becomes somewhat more effective when the two beams are present. The present finding is thus complementary to the work by Ganse et al.
Key words: plasmas – radiation mechanisms: non-thermal – solar wind – Sun: radio radiation – turbulence – waves

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