The constraint of plasma power balance on runaway avoidance

In a post-thermal-quench plasma, mitigated or unmitigated, the plasma power balance is mostly between collisional or Ohmic heating and plasma radiative cooling. In a plasma of atomic mixture {n alpha } with alpha labeling the atomic species, the power balance sets the plasma temperature, ion charge state distribution {n(alpha)(i)} with i the charge number, and through the electron temperature T-e and ion charge state distribution {n(alpha )(i)}, the parallel electric field E-ll. Since the threshold electric field for runaway avalanche growth E-av is also set by the atomic mixture, ion charge state distribution and its derived quantity, the electron density n(e), the plasma power balance between Ohmic heating and radiative cooling imposes a stringent constraint on the plasma regime for avoiding and minimizing runaways when a fusion-grade tokamak plasma is rapidly terminated.