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.

Automated summary

In a post-thermal-quench plasma, the power balance between collisional or Ohmic heating and plasma radiative cooling determines the plasma temperature, ion charge state distribution, parallel electric field, and electron density. These factors also set the threshold electric field for runaway avalanche growth, which is important for avoiding and minimizing runaways in fusion-grade tokamak plasmas during rapid termination.