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Найдено 8 публикаций
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Статья
Ruderman M., Petrukhin N., Pelinovsky E. Solar Physics. 2021. Vol. 296.
Добавлено: 18 августа 2021
Статья
I.A. Bakunina, Melnikov V., Solov'ev A. et al. Solar Physics. 2015. Vol. 290. No. 1. P. 37-52.

Мы исследовали ряд солнечных активных областей, используя микроволновые наблюдения с дву-мерным пространственным разрешением. Данные радиогелиографов в Нобеяме, Япония (NoRH) и Сибирского Солнечного Радиотелескопа, Бурятия (ССРТ) совместно с данными магнитографа Michelson Doppler Imager (MDI) на борту Солнечной и Гелиосферной обсерватории SOHO позволили нам идентифицировать долгоживущие межпятенные источники (МПИ) в большинстве исследованных активных областей. Их центры часто располагаются над нейтральной линией магнитного поля, которая разделяет лидирующую и последующую полярности всей активной области (первый тип МПИ) или  над линией инверсии магнитного поля, разделяющей магнитные полярности внутри комплекса пятен (второй тип МПИ). МПИ первого типа - протяженные источники, в основном, теплового тормозного излучения. МПИ второго типа - компактные источники, наиболее вероятно, гирорезонансной или гиросинхротронной природы. Мы предлагаем качественную модель трех магнитных потоков для объяснения генерации долгоживущих МПИ.

Добавлено: 8 сентября 2014
Статья
Petrukhin N., Ruderman M., Pelinovsky E. Solar Physics. 2015. Vol. 290. No. 5. P. 1323-1335.

We study the propagation of pulses of kink waves in magnetic-flux tubes. We use the thin-tube approximation and assume that the dependence of the phase speed on the distance along the tube is either linear or quadratic. In this case, the wave equation describing the propagation of kink waves reduces to the Klein–Gordon equation with constant coefficients. We present the general solution of the initial value–boundary value problem for this equation. Using this solution, we study the general properties of non-reflective pulse propagation. Then we apply the general results to the kink-pulse propagation in coronal magnetic loops. In particular, we suggest an alternative mechanism of small-amplitude decay-less kink oscillations in coronal loops

Добавлено: 4 августа 2015
Статья
Ruderman M., Pelinovsky E., Petrukhin N. et al. Solar Physics. 2013. Vol. 286. No. 2. P. 417-426.

Propagating kink waves are ubiquitously observed in solar magnetic wave guides. We consider the possibility that these waves propagate without reflection although there is some inhomogeneity. We briefly describe the general theory of non-reflective, one-dimensional wave propagation in inhomogeneous media. This theory is then applied to kink-wave propagation in coronal loops. We consider a coronal loop of half-circle shape embedded in an isothermal atmosphere, and assume that the plasma temperature is the same inside and outside the loop. We show that non-reflective kink-wave propagation is possible for a particular dependence of the loop radius on the distance along the loop. A viable assumption that the loop radius increases from the loop footpoint to the apex imposes a lower limit on the loop expansion factor, which is the ratio of the loop radii at the apex and footpoints. This lower limit increases with the loop height; however, even for a loop that is twice as high as the atmospheric scale height, it is small enough to satisfy observational constraints. Hence, we conclude that non-reflective propagation of kink waves is possible in a fairly realistic model of coronal loops.

Добавлено: 28 марта 2013
Статья
Pelinovsky E., Ruderman M., Petrukhin N. et al. Solar Physics. 2013. Vol. 286. P. 417-426.

Non-reflective propagation of kink waves in solar magnetic tubes.

Добавлено: 23 ноября 2013
Статья
Ruderman M. S., Petrukhin N., Pelinovsky E. Solar Physics. 2016. Vol. 291. No. 4. P. 1143-1157.

We study kink oscillations of thin magnetic tubes. We assume that the density inside and outside the tube (and possibly also the cross-section radius) can vary along the tube. This variation is assumed to be of such a form that the kink speed is symmetric with respect to the tube centre and varies monotonically from the tube ends to the tube centre. Then we prove a theorem stating that the ratio of periods of the fundamental mode and first overtone is a monotonically increasing function of the ratio of the kink speed at the tube centre and the tube ends. In particular, it follows from this theorem that the period ratio is lower than two when the kink speed increases from the tube ends to its centre, while it is higher than two when the kink speed decreases from the tube ends to its centre. The first case is typical for non-expanding coronal magnetic loops, and the second for prominence threads. We apply the general results to particular problems. First we consider kink oscillations of coronal magnetic loops. We prove that, under reasonable assumptions, the ratio of the fundamental period to the first overtone is lower than two and decreases when the loop size increases. The second problem concerns kink oscillations of prominence threads. We consider three internal density profiles: generalised parabolic, Gaussian, and Lorentzian. Each of these profiles contain the parameter αα that is responsible for its sharpness. We calculate the dependence of the period ratio on the ratio of the mean to the maximum density. For all considered values of αα we find that a formula relating the period ratio and the ratio of the mean and maximum density suggested by Soler, Goossens, and Ballester (Astron. Astrophys. 575, A123, 2015) gives a sufficiently good approximation to the exact dependence.

Добавлено: 2 июня 2016
Статья
Petrukhin N., Ruderman M. S. Solar Physics. 2021. Vol. 296.
Добавлено: 1 июля 2021
Статья
Shapoval A., Le Mouël J., Shnirman M. et al. Solar Physics. 2015. Vol. 290. No. 10. P. 2709-2717.
Добавлено: 20 ноября 2015