Alfvén eigenmode studies on JET

Valentin Aslanyan

MIT

Thursday, October 19, 2017

11:00am

NW17-

PSFC Seminars

Abstract: Alfvén waves are a generic phenomenon in magnetized plasmas, appearing in stellar coronas and the atmosphere. In magnetic fusion devices, they manifest themselves due to periodic variations of the magnetic field and are resonantly driven by slowing down fast particles. This has motivated many theoretical and experimental studies of Alfvén Eigenmodes (AEs), which may be driven violently unstable by the slowing down of fusion products in burning plasmas. Experiments to probe AEs with a resonant magnetic field have been undertaken on JET for 20 years. An upgrade to the AE active diagnostic (AEAD) antennas has recently been completed with the aim of measuring the modes' damping rates in upcoming DT experiments. The frequency range of the diagnostic has been extended downwards allowing detection of Beta (Acoustic) AEs and Geodesic Acoustic Modes, whose understanding is increasingly seen as important to future machines.

Bio: Graduated from the University of Oxford with a Master's in Physics in 2012. Completed PhD at the University of York, UK, in 2016 as part of the Fusion Doctoral Training Network. Thesis title: "Extreme ultraviolet lasers and their interactions with matter". Currently postdoc supervised by Prof Porkolab, seconded to the JET tokamak.