The constraint of plasma power balance on runaway avoidance

Abstract

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 $E_{\parallel }.$ 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.

References in corpus (5)

• Influence of massive material injection on avalanche runaway generation during tokamak disruptions
• Effect of partially-screened nuclei on fast-electron dynamics
• Effect of Two-Stage Shattered Pellet Injection on Tokamak Disruptions
• Effect of bremsstrahlung radiation emission on fast electrons in plasmas
• Impact of a minority relativistic electron tail interacting with a thermal plasma containing high-atomic-number impurities

Cited by in corpus (2)

• An upper pressure limit for low-Z benign termination of runaway electron beams in TCV
• First numerical analysis of runaway electron generation in tungsten-rich plasmas towards ITER