Stability of the steady-state course of a thermonuclear reaction in an inhomogeneous plasma

A method has been developed for investigating the stability of a steady-state thermonuclear reaction in an inhomogeneous plasma. It has been shown that “thermonuclear burning” is unstable with respect to the excitation of axisymmetric temperature fluctuations (m = 0) homogeneous along the magnetic field (k z = 0) if the temperature T m at the axis of the plasma column is lower than some value T * . This value is determined by the condition a (T m = T * ) = a min , where a min is the smallest plasma column radius at which the energy losses of the plasma can be compensated by the energy released as a result of thermonuclear reactions. The stability of the plasma energy balance in relation to temperature fluctuations with m≠0 and k z ≠0 is discussed. It has been assumed that the temperature at the plasma surface is lower than the ignition temperature of the thermonuclear reaction. It has also been assumed that the plasma energy confinement time is short in comparison with the particle confinement time.