naa a22 4500 510732038 CHVBK 20180411082956.0 cr unu---uuuuu 180411e20130601xx s 000 0 eng 10.1134/S1063772913050077 doi (NATIONALLICENCE)springer-10.1134/S1063772913050077 Prudskikh V. Research Institute of Physics, Southern Federal University, Rostov-on-Don, Russia aut Periodic instabilities in protostellar disks with azimuthal magnetic fields [Elektronische Daten] [V. Prudskikh] The stability of magnetohydrodynamic oscillations in a protostellar disk with a toroidal magnetic field is analyzed. It is shown that, apart from the aperiodic magnetorotational instability, two other types of periodic instabilities of non-axisymmetric perturbations can exist. The simultaneous presence of azimuthal and vertical components of the wave vector are necessary for these to exist. One instability is due to the inductive winding-up of the azimuthal magnetic field of the wave, and the other arises when the field amplitude is increased by a comoving Hall wave, transferring magnetic field into a region of enhanced field intensity. The bandwidths of the unstable wave numbers are analyzed as a function of the Hall current, the β parameter of a plasma, and the angle between the direction of wave propagation and the plane of the disk. Regions in the accretion disks typical of T Tauri stars are indentified where these instabilities could be most active. Pleiades Publishing, Ltd., 2013 Astronomy Reports SP MAIK Nauka/Interperiodica 57/6(2013-06-01), 440-447 1063-7729 57:6<440 2013 57 11444 https://doi.org/10.1134/S1063772913050077 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1134/S1063772913050077 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Prudskikh V. Research Institute of Physics, Southern Federal University, Rostov-on-Don, Russia aut NATIONALLICENCE 773 0- Astronomy Reports SP MAIK Nauka/Interperiodica 57/6(2013-06-01), 440-447 1063-7729 57:6<440 2013 57 11444 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer