Solnechno-Zemnaya Fizika Solnechno-Zemnaya Fizika Солнечно-земная физика 2712-9640 23985 10.12737/szf-53201905 Результаты исследований Results of current research Результаты исследований Effect of large-scale inhomogeneity of solar wind velocity on distribution of directions of interplanetary magnetic field vector Влияние крупномасштабной неоднородности скорости солнечного ветра на распределение направлений вектора межпланетного магнитного поля Ерофеев Дмитрий Викторович Erofeev Dmitry Viktorovich dve_08@mail.ru Уссурийская астрофизическая обсерватория ДВО РАН Уссурийск Россия Ussuriisk Astrophysical Observatory, FEB RAS Ussuriisk Russian Federation 5 3 50 63 https://zh-szf.ru/en/nauka/article/23985/view

По данным с часовым разрешением, полученным в околоземной гелиосфере в 1965–2014 гг., рассчитаны статистические характеристики углов, описывающих направление межпланетного магнитного поля (ММП): среднеквадратичные отклонения азимута и наклонения, коэффициенты асимметрии их распределений, а также коэффициент корреляции этих углов. Показано, что все перечисленные характеристики изменяются в цикле солнечной активности, причем часть изменяет знак при изменении направления полярного магнитного поля Солнца. Результаты обработки экспериментальных данных сравнивались с моделью, которая описывает перенос неоднородным солнечным ветром крупномасштабных возмущений силовых линий магнитного поля. Сравнение показало, что изменение характеристик углового распределения ММП в солнечном цикле, вероятно, происходит вследствие появления крупномасштабного широтного градиента скорости солнечного ветра в периоды минимумов солнечной активности. Существенное влияние на угловое распределение ММП оказывают также долготный градиент скорости в хвостовых частях высокоскоростных потоков и кратковременные локальные вариации градиентов скорости.

Using data with hourly resolution obtained in near-Earth heliosphere in 1965–2014, we have calculated statistical characteristics of the angles describing the direction of the interplanetary magnetic field (IMF): root-mean-square deviations of azimuthal and elevation angles, asymmetries of their distributions, and coefficient of correlation of the angles. It has been shown that the above characteristics varied in the course of solar cycle, and some of them changed their signs when solar polar magnetic field reversed. The results obtained from the experimental data analysis were compared with a model describing transport of large-scale disturbances of IMF lines by the inhomogeneous solar wind. The comparison has shown that the variations in the angular distribution of IMF in the course of solar cycle probably occur due to the appearance of the large-scale latitudinal gradient of solar wind velocity during solar minima. In addition, the angular distribution of IMF has been found to be substantially affected by the longitudinal velocity gradient in trailing parts of high-speed streams and short-term local-scale variations in velocity gradients.

 межпланетное магнитное поле солнечный ветер солнечный цикл interplanetary magnetic field solar wind solar cycle

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