https://fusion.zoom.us/j/99156454238?pwd=U2VROXlrdEVEQTA1aVJkM0VIQVlUZz09
Abstract: In the presence of a sufficiently strong electric field electrons moving through a plasma experience free-fall acceleration to relativistic energies. These so called "runaway" electrons exist in lightning discharges and drive Whistler waves in the planetary ionosphere. The conditions required to create these relativistic electrons is also present during tokamak disruptions where the plasma current is terminated quickly and sometimes unexpectedly. In future fully nuclear tokamak devices such as ITER in SPARC runaway electrons will be created through four primary mechanisms and the secondary avalanche mechanism. This avalanche mechanism scales as the exponential of the pre-disruption plasma current and is therefore expected to create energetic beams with MA's of current and MeV's of energy in these future high plasma current devices. These beams therefore have the potential to seriously damage plasma facing components and are seen as one of the major unresolved issues for the tokamak concept. This talk will outline the fundamental physics of runaway electrons and discuss concepts currently under development to prevent their formation and mitigate their risk. These concepts include a passive runaway electron coil and wave-particle interactions.