Effects of hot electrons on magnetohydrodynamic modes in ELMO Bumpy Torus

The effect of hot electrons on magnetohydrodynamic instabilities is studied using a fully electromagnetic, finite β, Vlasov–Maxwell model consisting of three species in an inhomogeneous slab geometry with gravity. If no hot electrons are present, the Vlasov model agrees with well-known results from the magneto-hydrodynamic model. If the density of hot electrons is small, but their temperature is sufficiently large, the Vlasov model predicts stabilization of magnetohydrodynamic modes in certain parameter regimes. For ELMO Bumpy Torus parameters this occurs at β=10%–20%, which is in agreement with experimental observations. Comparison is also made with a model that assumes the hot electrons form a rigid non-interacting current. It is found that while the latter model can qualitatively predict the low β stability threshold, it is overly optimistic in describing the finite β behavior.