Thermomagnetic instability in hot spherical plasma shells

A linear stability analysis of ionized spherical plasma shells with radial temperature gradients and an external poloidal magnetic field is presented. It is shown that both hydromagnetic and thermomagnetic effects can lead to an amplification of waves. Solutions are obtained for a wide range of plasma beta values and the thermomagnetic transport coefficient. The conditions under which the instability grows are found and the characteristic growth rates are calculated. The regime at which the thermomagnetic instability is effective is considered. Applications for the solar corona are discussed.