The ion-acoustic instability in the pre-flare plasma near the loop footpoints at solar active regions

Kryshtal, A. N.; Gerasimenko, S. V.; Voitsekhovska, A.D.; Fedun, V.

doi:10.5194/angeo-31-2193-2013

Cited by 7 publications

(9 citation statements)

References 26 publications

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“…Ïîäîáíûå ôàêòû òðåáóþò ñâîåãî îáúÿñ íåíèÿ èëè íà óðîâíå íîâîé òåîðèè, èëè íà óðîâíå îðèãèíàëüíîé êîíöåïöèè èññëåäîâàíèé. Òàêàÿ êîíöåïöèÿ, ïðåäëîaeåííàÿ íàìè â ðàáîòàõ [35][36][37][38][39][40][41], ïðèìåíÿåòñÿ è â íàñòîÿùåé ðàáîòå äëÿ ðåøåíèÿ êîíêðåòíîé çàäà÷è. Ôîóêàë è Õèíàòà [25] ïåðâûìè ïðåäëîaeèëè ñ÷èòàòü äîïîëíèòåëüíîå øòàðêîâñêîå óøèðåíèå ëèíèé áàëüìåðîâñêîé ñåðèè ñ áîëüøèìè íîìåðàìè (N ³ 8) ñâèäåòåëüñòâîì íàëè÷èÿ â ñîëíå÷íîé àòìîñôåðå, â ÷àñòíîñòè â ìàãíèòíûõ ïåòëÿõ, êðóïíîìàñøòàáíîãî êâàçèñòà -òè÷åñêîãî ñëàáîãî ýëåêòðè÷åñêîãî ïîëÿ.…”

Section: âñòóïëåíèåunclassified

“…Â íàñòîÿùåå âðåìÿ ôàêò íàëè ÷èÿ òàêîãî ïîëÿ èìååò, êðîìå ïðÿìûõ [31,48], öåëûé ðÿä êîñâåííûõ ïîäòâåðaeäåíèé, ñðåäè êîòîðûõ ìîaeíî íàçâàòü äîïîëíèòåëüíîå èçëó÷åíèå èç îñíîâàíèé âñïûøå÷íûõ ïåòåëü, íàáëþäàåìîå íà ïðîòÿaeåíèè ìèêðîâîëíîâûõ âñïëåñêîâ, ïðîòÿaeåííûå òåïëîâûå èñòî÷íèêè, õîðîøî âèäíûå â êîðîíàëüíîé ÷àñòè ïåòåëü, íåèçìåííîå ïîïåðå÷íîå ñå÷åíèå òàê íàçûâàåìûõ «ìÿãêèõ ðåíòãåíîâñêèõ ïåòåëü», ÷åòêàÿ êîððåëÿöèÿ «øèðà» ôîòîñôåðíîãî ìàãíèòíîãî ïîëÿ ñ óâåëè -÷åíèåì êîðîíàëüíîãî íàãðåâà è öåëûé ðÿä äðóãèõ ÿâëåíèé [16,48]. Ñîãëàñíî èñïîëüçóåìîé íàìè êîíöåïöèè èññëåäîâàíèÿ íåóñòîé÷èâîñòåé ìåëêîìàñøòàáíûõ ïëàçìåííûõ âîëí â ïåòåëüíûõ ñòðóêòóðàõ àêòèâíîé îáëàñòè [35][36][37][38][39][40][41] òàêèå âîëíû ìîãóò ïîÿâèòüñÿ èìåííî âñëåä ñòâèå ðàçâèòèÿ íåóñòîé÷èâîñòåé íà ñàìûõ ðàííèõ ñòàäèÿõ ðàçâèòèÿ âñïûøå÷íîãî ïðîöåññà êàê ðàç áëàãîäàðÿ íàëè÷èþ âûøåóïîìÿíóòîãî ýëåêòðè÷åñêîãî ïîëÿ [1,7,25,26,45]. Â ðàáîòå Ìèëëåðà è äð.…”

Section: âñòóïëåíèåunclassified

“…Òàêèì îáðàçîì, íàëè÷èå ñóáäðåéñåðîâñêîãî ýëåêòðè÷åñêîãî ïîëÿ ìîaeåò ïðèâåñòè ê âîçíèêíîâåíèþ ðàçëè÷íîãî âèäà ïëàçìåííûõ íåóñòîé÷èâîñòåé, à â ïðîöåññå èõ ðàçâèòèÿ -è ê âîçìîaeíîé èõ òðàíñôîðìàöèè â ìåëêîìàñøòàáíóþ òóðáóëåíòíîñòü çàäîëãî äî íà÷àëà ôàçû ïðåäâàðèòåëüíîãî íàãðåâà. Î÷åâèäíî, ÷òî àìïëèòóäû ýòèõ âîëí íà ïðîòÿaeåíèè ëèíåéíîé ñòàäèè ðàçâèòèÿ íà÷àëüíîãî âîçìóùåíèÿ íåíàìíîãî ïðåâûøàþò óðîâåíü òåïëîâûõ øóìîâ, îäíàêî âàaeíî òî, ÷òî ïîÿâëåíèå ñðåäè íèõ íåçàòóõàþùèõ âîëí ñ ìàëîé àìïëèòóäîé [35,[37][38][39][40] ìîaeåò èìåòü ñâîèì êîíå÷íûì ðåçóëüòàòîì ãåíåðàöèþ êðàòêîâðåìåííûõ âñïëåñêîâ ýëåêòðîìàãíèòíîãî èçëó÷åíèÿ â ìèêðîâîëíîâîì äèàïàçîíå [7,15,18,19]. Â ðàáîòå [6] ìû ïîêàçàëè, ÷òî äèñïåðñèîííîå óðàâíåíèå äëÿ íèçêî÷àñòîòíûõ êèíåòè÷åñêèõ íåóñòîé÷èâîñòåé â ïðåäâñïûøå÷íîé ïëàçìåííîé àòìîñôåðå àêòèâíîé îáëàñòè âáëèçè îñíîâàíèÿ ïåòëè èìå åò ÷åòûðå ðåøåíèÿ.…”

Section: âñòóïëåíèåunclassified

“…Â ðàáîòàõ [19,[28][29][30] áûëî ïîêàçàíî, ÷òî äàaeå ïîÿâëåíèå â ïðåäâñïûøå÷íîé ïëàçìå ìåëêîìàñøòàáíîé áåðíøòåéíîâñêîé òóðáóëåíòíîñòè íå âëèÿåò êðèòè÷åñêèì îáðàçîì íà âèä ðåøåíèé äèñïåðñèîííîãî óðàâíåíèÿ, ò. å. ðåøåíèÿ, ïðèíàäëåaeàâøèå ñåìåéñòâó ÊÀÂ èëè ñåìåéñòâó ÊÈÇÂ äî ïîÿâëåíèÿ â ïëàçìå òóðáóëåíòíîñòè, îñòàþòñÿ, ñëåãêà òðàíñôîðìèðóÿñü, â ïðåäåëàõ òîãî aeå ñåìåéñòâà è ïîñëå ïîÿâëåíèÿ òóðáóëåíòíîñòè. Â ðàáîòå [6] ïðåäïîëàãàëîñü, ÷òî ìåëêîìàñøòàáíàÿ òóðáóëåíòíîñòü âîçíèêàåò âñëåäñòâèå ðàçâèòèÿ íåóñòîé÷èâîñòè âòîðîé ãàðìîíèêè êâàçèáåðíøòåéíîâñêèõ ìîä [38][39][40][41], à ãåíåðàöèÿ ÊÀÂ è ÊÈÇÂ íà åå ôîíå âîçìîaeíà áëàãîäàðÿ îãðîìíîé ðàçíèöå ïîðîãîâûõ çíà÷åíèé îñíîâíîãî èñòî÷íèêà íåóñòîé÷èâîñòè, -ñóáäðåéñåðîâñêîãî ýëåêòðè÷åñêîãî ïîëÿ äëÿ âòîðîé ãàðìîíèêè è äëÿ êèíåòè÷åñêèõ âîëí. Ïðè ýòîì î÷åíü âàaeíî çíàòü îòâåò íà âîïðîñ, íå ðàçðóøèò ëè ïîÿâëåíèå òóðáóëåíòíîñòè â ïðåäâñïûøå÷íîé ïëàçìå ïðîöåññ ãåíåðàöèè íèçêî÷àñòîòíûõ êèíåòè -÷åñ êèõ âîëí?…”

Section: âñòóïëåíèåunclassified

“…Ñîîòíîøåíèå (6) ìîaeíî âûðàçèòü â åäèíèöàõ àìïëèòóäû ëîêàëüíîãî äðåéñåðîâñêîãî ïîëÿ: e R óäîáíåå èñïîëüçîâàòü ãåîìåòðè÷åñêèå õà ðàêòåðèñòèêè ïåòëè (òàêaeå íà óðîâíå îöåíîê, ó÷èòûâàÿ ðåàëüíóþ ðàç ðåøàþùóþ ñïî ñîáíîñòü äàaeå ëó÷øèõ ñîâðåìåííûõ ïðèáîðîâ) è âåëè ÷èíó ïîëíîãî òîêà â íåé [32,42,48,49]. Â ðàñ÷åòàõ â äàííîé ðàáîòå ìû èñïîëüçîâàëè çíà÷åíèå ( ) max e R = 0.20 [6,[38][39][40]. Âûáèðàÿ ðåàëèñòè÷ íûé èíòåðâàë èçìåíåíèÿ àìïëèòóäû ìàãíèòíîãî ïîëÿ â ïåòëå â èññëåäóåìîì äèàïàçîíå âûñîò, ìû ðóêîâîäñòâîâàëèñü ñëåäóþùèìè ñîîáðàaeåíèÿìè.…”

Section: ìîäåëü ïðåäâñïûøå×íîé ïëàçìû è èñïîëüçóåìûå ïðèáëèAeåíèßunclassified

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Section: ìîäåëü ïðåäâñïûøå×íîé ïëàçìû è èñïîëüçóåìûå ïðèáëèAeåíèßunclassified

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Oblique Bernstein Mode Generation Near the Upper-hybrid Frequency in Solar Pre-flare Plasmas

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We study analytically the generation process of the first harmonics of the pure electron weakly oblique Bernstein modes. This mode can appear as a result of the rise and development of a corresponding instability in a solar active region. We assume that this wave mode is modified by the influence of pair Coulomb collisions and a weak large-scale sub-Dreicer electric field in the pre-flare chromosphere near the footpoints of a flare loop. To describe the pre-flare plasma we used the model of the solar atmosphere developed by Fontenla, Avrett, and Loeser (Astrophys. J. 406, 319, 1993). We show that the generated first harmonic is close to the upper-hybrid frequency. This generation process begins at the very low threshold values of the sub-Dreicer electric field and well before the beginning of the preheating phase of a flare. We investigate the necessary conditions for the existence of non-damped first harmonics of oblique Bernstein waves with small amplitudes in the flare area.

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Nonlinear interaction of kinetic Alfvén waves and ion acoustic waves in coronal loops

2016

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Over the years, coronal heating has been the most fascinating question among the scientific community. In the present article, a heating mechanism has been proposed based on the wave–wave interaction. Under this wave–wave interaction, the high frequency kinetic Alfvén wave interacts with the low frequency ion acoustic wave. These waves are three dimensionally propagating and nonlinearly coupled through ponderomotive nonlinearity. A numerical code based on pseudo-spectral technique has been developed for solving these normalized dynamical equations. Localization of kinetic Alfvén wave field has been examined, and magnetic power spectrum has also been analyzed which shows the cascading of energy to higher wavenumbers, and this cascading has been found to have Kolmogorov scaling, i.e., k−5/3. A breakpoint appears after Kolmogorov scaling and next to this spectral break; a steeper scaling has been obtained. The presented nonlinear interaction for coronal loops plasmas is suggested to generate turbulent spectrum having Kolmogorov scaling in the inertial range and steepened scaling in the dissipation range. Since Kolmogorov turbulence is considered as the main source for coronal heating; therefore, the suggested mechanism will be a useful tool to understand the mystery of coronal loop heating through Kolmogorov turbulence and dissipation.

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The ion-acoustic instability in the pre-flare plasma near the loop footpoints at solar active regions

Cited by 7 publications

References 26 publications

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Untitled

Oblique Bernstein Mode Generation Near the Upper-hybrid Frequency in Solar Pre-flare Plasmas

Nonlinear interaction of kinetic Alfvén waves and ion acoustic waves in coronal loops

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