Comparison of electron cyclotron emission models for application of ECE diagnostics on Alcator C‑Mod, SPARC, and nT-Tao devices.

Electron cyclotron emission (ECE) radiometry is a well-established diagnostic technique capable of providing high spectral and temporal resolution measurements of electron temperature profiles in toroidally confined plasmas. Modeling electron cyclotron emission and absorption is important for understanding ECE diagnostic measurement localization and resolution. This poster will compare two different formulations for ECE. The starting point is ECESIM tool [1], which uses a Vlasov-Maxwell coupled system and power transfer for calculation of optical constants [2]. This established framework is compared with a further enhanced model, which includes Coulomb collisions, wave diffusion effects in the kinetic equation and generalized electron distribution functions [3]. Calculations are compared with experimental ECE measurements from Alcator C-Mod. In addition, predictions of ECE emission and absorption are performed for two developing devices: SPARC and nT-Tao. The extension to non-thermal electrons is particularly valuable for interpretation of ECE measurements during anomalous scenarios, such as heating or instabilities, and presents a potential for the investigation of the ECE-Thomson discrepancy. 

[1] M.E. Austin, U. Texas FRC Report #534

[2] M. Bornatici et al 1983 Nucl. Fusion 23 1153 

[3] G. Giruzzi 1988 Nucl. Fusion 28 1413 

Research sponsored by DOE contract number DE-SC0014264 and by sponsored research agreements with companies nT-Tao and CFS.