On the possibility of langmuir turbulence development at the early stage of a flare process

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Astronomy and Astrophysics
1Kryshtal, AN, 2Gerasimenko, SV, 1Voitsekhovska, AD, 2Soloviov, AA
1Main Astronomical Observatory of the NAS of Ukraine, Kyiv, Ukraine
2Main Astronomical Observatory of the National Academy of Sciences of Ukraine, Kyiv, Ukraine
Kosm. nauka tehnol. 2009, 15 ;(5):59-67
https://doi.org/10.15407/knit2009.05.059
Publication Language: Russian
Abstract: 
We investigated some conditions of the appearance of high-frequency electron langmuir wave instability in a plasma near the foot-point of the loop structure at the early stage of a flare process in a solar active region (AR). The process of the instability rise and development is a result of the combined action of the following factors: the existence of a weak large-scale electric field in the loop current circuit, influence of the pair Coulomb collisions, loss of electron momentum due to the interaction with the pulsations of saturated Bernstein turbulence and Landau damping. It is assumed that near the loop footpoint, in the region of «kilogauss» magnetic fields, the plasma density and temperature are determined in the framework of the semiempirical model FAL (Fontenla-Avrett-Loeser) for solar atmosphere which takes into account the helium diffusion process. We performed the comparison of the obtained results with the analogous results derived in the framework of alternative models MAVN (Machado-Avrett-Vernazza-Noyes) and VAL (Vernazza-Avrett-Loeser) for the solar atmosphere.
Keywords: active region, langmuir wave, loop structure
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