Quasibernstein modes in preflare atmosphere of Solar active region: the second harmonic generation

1Kryshtal, AN, 1Gerasimenko, SV, 2Voitsekhovska, AD
1Main Astronomical Observatory of the National Academy of Sciences of Ukraine, Kyiv, Ukraine
2Main Astronomical Observatory of the NAS of Ukraine, Kyiv, Ukraine
Kosm. nauka tehnol. 2010, 16 ;(6):40-50
https://doi.org/10.15407/knit2010.06.040
Publication Language: Russian
Abstract: 
The generation of the second harmonic during the development of the corresponding instability is investigated for the pure electron oblique Bernstein modes modified by taking into account Coulomb collisions and existence of the weak large-scale electric field in the post-flare loop. We propose to name such modes as quasibernsteinian ones. It is supposed that the main characteristics of magnetoactive plasma at the foot-points of the loop structures, which correspond to the “lower-middle” chromosphere of an active region (AR), are determined through the semiempirical model for the solar atmosphere of Fontenla‒Avrett‒ Loeser (FAL).
             It is been demonstrated that the use of this model instead of the models of Machado‒Avrett‒Vernaz-za‒Noyes (MAVN) and Vernazza‒Avrett‒Loeser (VAL) used before leads to considerable changes of the instability threshold values of subdreicer electric field amplitudes and boundary values of the perturbation wavelength. Microwave emission in the centimetre-millimetre interval can appear under favourable conditions due to the coalescence of two quasibernsteinian harmonics with next formation of electromagnetic wave. 
Keywords: loop structures, magnetoactive plasma, quasibernstein modes
References: 
1. Aleksandrov A. F., Bogdankevich L. S., Rukhadze A. A. Principles of Plasma Electrodynamics, 424 p. (Vysshaya Shkola, Moscow, 1989) [in Russian].
2. Antonov A. V., Gerasimov Yu. M., Karelin Yu. V. Research of Parameters of Solar Flares at 3-mm Wavelengths. Radio Physics and Radio Astronomy, 13 (1), 15—25 (2008) [in Russian].
3. Bogod V. M., Garaimov V. I., Zheleznyakov V. V., Zlotnik E. Ya. Detection of a Cyclotron Line in the Radio Spectrum of a Solar Active Region and Its Interpretation. Astron. zhurn., 77 (4), 313—320 (2000) [in Russian].
4. Gelfreikh G. B., Tsap Yu. T., Kopylova Yu. G., et al. Variations of Microwave Emission from Solar Active Regions. Pis'ma v Astron. zhurn., 30 (7), 540—547 (2004) [in Russian].
5. Gopasyuk S. I. Structure and dynamics of the magnetic field in active regions on the Sun., Itogi nauki i tehniki, VINITI, Astronomy, 34, 7—77 (1987) [in Russian].
6. Zheleznyakov V. V. Electromagnetic waves in cosmic plasma. Generation and propagation, 432 p. (Nauka, Moscow, 1977) [in Russian].
7. Zaitsev V.V., Stepanov A.V., Tsap Yu.T. On the problems of physics of solar and stellar flares. Kinematika i Fizika Nebesnykh Tel, 10 (6), 3—31 (1994) [in Russian].
8. Kopylova Yu. G., Stepanov A. V., Tsap Yu. T. Radial Oscillations of Coronal Loops and Microwave Radiation from Solar Flares. Pis'ma v Astron. zhurn., 28 (11), 870—879 (2002) [in Russian].
9. Kryshtal' A. N., Gerasimenko S. V. On the sequence of the rise of plasma wave instabilities near the footpoints of solar arch structures at the early stages of a flare process. Kinematika i Fizika Nebesnykh Tel, 21 (5), 352—367 (2005) [in Russian].
10. Melnikov V. F., Fleishman G. D., Fu Q. J., Huang G.-L. Flare-Plasma Diagnostics from Millisecond Pulsations of the Solar Radio Emission. Astron. zhurn., 79 (6), 551—569 (2002) [in Russian].
11. Podgorny A. I., Podgorny I. M. Numerical Simulation of a Solar Flare Produced by the Emergence of New Magnetic Flux. Astron. zhurn., 78 (1), 71—77 (2001) [in Russian].
12. Charikov Yu. E. Pre-flash stage of energy accumulation: new observations and possible mechanisms. In: Physical nature of solar activity and prediction of its geophysical manifestations: Theses of the 11th Pulkovo International. Conf. in physics
of the; GAO RAN, Pulkovo, St. Petersburg, July 2—7, 2007, 138—139 (St. Petersburg, 2007) [in Russian].
13. Chen F. F. Introduction to Plasma Physics, 398 p. (Mir, Moscow, 1987) [in Russian].
14. Yurovskii Yu. F. On mechanisms for modulating the radio emission of solar flares. Astron. zhurn., 74 (6), 347—360 (1997) [in Russian].
15. Antonov A. V., Bezuglaya G. V., Gerasimov Yu. V., Karelin Yu. V. Oscillation of radiotion of solar flares in 3mm range. MSMV’07 Symp. Proc., Kharkov, Ukraine, June 25—30, 2007, Vol. 2, 751—753 (Kharkov, 2007).
16. Aschwanden M. I. An evaluation of coronal heating models for active regions based on Yohkoh, SOHO and TRACE ob servations. Astrophys. J., 560, 1035— 1043 (2001).
https://doi.org/10.1086/323064
17. Aurass H. Radio type IV burst fine structures and the dynamics of flare process. In: Solar Coronal Structures: Proc. 144-th IAU Colloq., Bratislava, Slovakia, 20—24 September 1993, Eds V. Rusin, P. Heinzel, I.-C.Vial, 251—256 (VEDA Publ. Company, Bratislava, 1993).
18. Brinca A. L., Dysthe K. B. Effect of longitudinal electric fields on electrostatic electron cyclotron waves. J. Plasma Phys., 29 (1), 35—40 (1983).
https://doi.org/10.1017/S0022377800000556
19. Farnik F., Savy K. Soft X-ray pre-flare emission studied in Yohkoh-SXT images. Solar Phys., 183 (1), 339—357 (1998).
https://doi.org/10.1023/A:1005092927592
20. Fontenla J. M., Avrett E. H., Loeser R. Energy balance in solar transition region. III. Helium emission in hydrostatic, constant-abundance models with diffusion. Astrophys. J., 406 (1), 327—336 (1993).
https://doi.org/10.1086/172443
21. Foukal P., Hinata S. Electric fields in the solar atmosphere: a review. Solar Phys., 132 (1), 307—330 (1991).
https://doi.org/10.1007/BF00152291
22. Harra L. K., Matthews S. A., Culhane J. L. Nonthermal velocity evolution in the precursor phase of a solar flare. Astrophys. J., 549 (2), L245—L248 (2001).
https://doi.org/10.1086/319163
23. Heyvaerts J., Priest E., Rust D. An emerging flux model for the solar flare phenomenon. Astrophys. J., 216 (1), 213—221 (1977).
https://doi.org/10.1086/155453
24. Kryshtal A. N. Bernstein wave instability in a collisional plasma with a quasistatic electric field. J. Plasma Phys., 60 (3), 469—484 (1998).
https://doi.org/10.1017/S0022377898007004
25. Machado M. E., Avrett E. H., Vernazza J. E., Noyes R. W. Semiempirical models of chromospheric flare regions. Astrophys. J., 242 (1), 336—351 (1980).
https://doi.org/10.1086/158467
26. Schmahl E. I., Webb D. K., Woodgate B., et al. Coronal manifestations of preflare activity. Energetic Phenomena on the Sun (“Impulsive Phase Transport”), Eds M.Kundu and B.Woodgate, NASA CP — 2439, L48—L78 (Washington, DC, 1986).
27. Solanki S. K. Small-scale solar magnetic fields: an overview. Space Sci. Rev., 63, 1—183 (1993).
https://doi.org/10.1007/BF00749277
28. Vernazza J. E., Avrett E. H., Loeser R. Structure of the solar chromosphere. III-Models of the EUV brightness components of the quiet-sun. Astrophys. J. Suppl. Ser., 45 (1), 635—725 (1981).
https://doi.org/10.1086/190731

29. Willes A. J., Robinson P. A. Electron-cyclotron maser theory for noninteger radio emission frequencies in solar microwave spike bursts. Astrophys. J., 467 (1), 465—472 (1996).
https://doi.org/10.1086/177620