Differential Cross-Field Ion Transport and Temperature Screening from a Thermodynamic Perspective

The cross-field accumulation of high-Z impurities follows obeys the same equilibrium condition across a surprisingly wide variety of systems. Information theory and thermodynamics provide a set of tools that makes it possible to explain this behavior in terms of a minimal set of requirements, without any need to solve to the system's equations of motion directly. For a system without temperature gradients, familiar results from impurity transport theory can be recovered by imposing an ambipolarity condition and calculating the system's maximum-entropy state [1]. For a system with temperature gradients, temperature-screening effects can be recovered in a generic linear-response theory by combining ambipolarity with certain symmetries of the transport matrix [2].

[1] E. J. Kolmes, I. E. Ochs, M. E. Mlodik, and N. J. Fisch, Maximum-Entropy States for Magnetized Ion Transport, Phys. Lett. A 384, 126262 (2020).

[2] E. J. Kolmes, I. E. Ochs, M. E. Mlodik, and N. J. Fisch, Temperature Screening and Cross-Field Impurity Accumulation from a Thermodynamic Perspective, in press at Phys. Lett. A.