Abstract Details
Abstracts
Author: Francois L. Waelbroeck
Requested Type: Poster
Submitted: 2023-04-03 11:05:22
Co-authors: S. Cancino, J. Martinell, R. Fitzpatrick
Contact Info:
Univ. Texas at Austin
2515 Speedway
Austin, TX 78712-1203
US
Abstract Text:
Plasma inhomogeneity can create magnetic islands through instabilities such as the neoclassical tearing mode (NTM), which is driven by the pressure gradient through the agency of the bootstrap current. Plasma inhomogeneity also affects how the plasma responds to applied resonant perturbations, such as those used for ELM control in tokamaks and for creating island divertors in stellarators. This presentation will describe the extension of the IslET fluid model (Island Equilibrium and Transport [1]) to describe ion compressibility, thereby allowing the tearing mode to radiate drift-acoustic waves. Analytic solutions of the IslET model will be presented in the unmagnetized regime. This regime (also called the supersonic regime [2]) is such that islands are wider than the width of the current channel found in linear theory but narrower than the ion-acoustic gyro-radius, rhos=Cs/Omega_ci where Cs=Sqrt[Te/Mi] is the sound speed. The new solutions extend a previous analysis [2] by removing the assumption that the phase velocity of the island is close to the electron drift velocity, thereby allowing the description of the acoustic braking and healing of the island away from the electron diamagnetic drift velocity and towards the plasma frame (ExB or electric drift velocity).
[1] FL Waelbroeck, Phys. Rev. Lett. 95, 035002 (2005).
[2] R Fitzpatrick and FL Waelbroeck, Phys. Plasmas 15, 012502 (2008).
This research was funded by PAPIIT-IN110021 and CONACyT A1-S-25157. One of us (FW) was funded by the Office of Fusion Energy Sciences of the U.S. Department of Energy under Grant DE-FG02-04ER54742.
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