Magnetic field gradient effects on the magnetorotational instability
Küçük Resim Yok
Tarih
2017
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Wiley-VCH Verlag
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
Magnetorotational instability (MRI), also known as the Balbus–Hawley instability, is thought to have an important role on the initiation of turbulence and angular momentum transport in accretion disks. In this work, we investigate the effect of the magnetic field gradient in the azimuthal direction on MRI. We solve the magnetohydrodynamic equations by including the azimuthal component of the field gradient. We find the dispersion relation and calculate the growth rates of the instability numerically. The inclusion of the azimuthal magnetic field gradient produces a new unstable region in the wavenumber space. It also modifies the growth rate and the wavelength range of the unstable mode: the higher the magnitude of the field gradient, the greater the growth rate and the wider the unstable wavenumber range. Such a gradient in the magnetic field may be important in T Tauri disks, where the stellar magnetic field has an axis that is misaligned with respect to the rotation axis of the disk. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Açıklama
Anahtar Kelimeler
accretion, accretion disks — instabilities — MHD
Kaynak
Astronomische Nachrichten
WoS Q Değeri
Scopus Q Değeri
Q3
Cilt
338
Sayı
6
