UDK 53 Физика
UDK 520 Инструменты, приборы и методы астрономических наблюдений, измерений и анализа
UDK 521 Теоретическая астрономия. Небесная механика. Фундаментальная астрономия. Теория динамической и позиционной астрономии
UDK 523 Солнечная система
UDK 524 Звезды и звездные системы. Вселенная Солнце и Солнечная система
UDK 52-1 Метод изучения
UDK 52-6 Излучение и связанные с ним процессы
GRNTI 41.00 АСТРОНОМИЯ
GRNTI 29.35 Радиофизика. Физические основы электроники
GRNTI 29.31 Оптика
GRNTI 29.33 Лазерная физика
GRNTI 29.27 Физика плазмы
GRNTI 29.05 Физика элементарных частиц. Теория полей. Физика высоких энергий
OKSO 03.06.01 Физика и астрономия
OKSO 03.05.01 Астрономия
OKSO 03.04.03 Радиофизика
BBK 2 ЕСТЕСТВЕННЫЕ НАУКИ
BBK 223 Физика
TBK 614 Астрономия
TBK 6135 Оптика
BISAC SCI004000 Astronomy
BISAC SCI005000 Physics / Astrophysics
We study numerically the gravitational fragmentation of a cylindrical molecular cloud with large-scale magnetic field. The simulations are performed with the help of the MHD code FLASH. We consider two cases: gravitational instability of the filament with initially deformed surface (model of Chandrasekhar and Fermi), and the instability of longitudinal compressible waves (model of Stodolkeiwicz). The simulations under typical parameters show that two types of the cores can be formed as a result of the fragmentation. Gravitational focusing leads to the formation of two massive clumps at the ends of filaments. Those cores move towards the cloud center with supersonic speeds. The instability of initial perturbations results in smaller evenly distributed cores inside the filament. The cores formed due to the instability of compressible waves have almost spherical shapes, while the cores resulted from the fragmentation of the filament with deformed surface are flattened. Typical sizes of the cores of 0.01–0.02 pc are in agreement with observations.
ISM: clouds, evolution, magnetic fields; magnetohydrodynamics (MHD); methods: numerical
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