Curvature‐driven instabilities in a hot electron plasma: Radial analysis

The theory of curvature‐driven instabilities is developed for a plasma interacting with a hot electron ring whose drift frequencies are larger than the growth rates predicted from conventional magnetohydrodynamic theory. A z‐pinch model is used to emphasize the radial structure of the problem. Stability criteria are obtained for the five possible modes of instability: the conventional hot electron interchange, a high‐frequency hot electron interchange (at frequencies larger than the ion cyclotron frequency), a compressional instability, a background pressure‐driven interchange, and an interacting pressure‐driven interchange. Numerical plots of the marginal stability boundaries are presented for parameter values corresponding to the EBT‐S and EBT‐P bumpy torus experiments.