Sherwood 2015

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Global vs local gyro-kinetic studies of core micro-instabilities in JET hybrid discharges with ITER like wall

Author: Sara Moradi
Requested Type: Consider for Invited
Submitted: 2015-01-20 01:30:17

Co-authors: I. Pusztai, J. Citrin, Hyun-Tae Kim, I. Lupelli and the JET contributors

Contact Info:
Ecole Polytechnique, CNRS UMR7648, LPP, F-91128, P
Rute Saclay 1
Palaiseau, Ils-de-fra   91128

Abstract Text:
In recent years there has been an increasing worldwide effort to further the development of the so-called hybrid or improved H-mode scenarios. In these plasmas, representing a hybrid between "baseline" and "advanced tokamak" scenarios, enhanced normalized confinement is achieved (compared to the ITER baseline ELMy H-mode) through current profile optimization. We present a study on the characteristics of core microinstabilities in two hybrid plasmas from recent JET experiments with ITER like wall (selected from Ref. [1] based on local and global gyro kinetic simulations with the GYRO code [2]. In particular, we study the role of normalized plasma pressure and fast ions on the micro-instabilities. We examine the role of different plasma parameters responsible for the onset and stabilization of modes found under experimental conditions by scanning the parameter space at three different radial locations. We put special emphasis on probing the importance of whether a global or local approach is used for the plasma stability analysis under these plasma conditions. The results are compared to our previous study of hybrids at JET with carbon wall [3].
The authors would like to thank J Candy for providing the GYRO code. This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014-2018 under grant agreement No 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission.

[1] C. Challis et al, Proceedings of the 25th IAEA Fusion Energy Conference 2014, Saint Petersburg, Russia, EX/9-3 (2014).
[2] J. Candy and E. Belli, General Atomics Report GA-A26818 (2011).
[3] S. Moradi et al, Nucl. Fusion, 54, 123016 (2014).


March 16-18, 2015
The Courant Institute, New York University