Woodruff School of Mechanical Engineering

NRE 8011/8012 and MP 6011/6012 Seminar

Nuclear & Radiological Engineering and Medical Physics Programs


Tokamak Plasmas with Intrinsic Suppression of Edge Localized Modes


Dr. Theresa Wilks


Research Scientist, Massachusetts Institute of Technology Plasma Science and Fusion Center


Thursday, September 20, 2018 at 11:00:00 AM


Boggs Building, Room 3-47


Weston Stacey


Economical and reliable fusion reactor designs require plasma operating regimes that sustain density control via particle transport, while maintaining high thermal confinement. High confinement (H-mode) plasmas in current machines can maintain these characteristics, with the particle transport enhanced by edge localized modes (ELMs), which are quasi-periodic edge relaxation events thought to develop from magnetohydrodynamic (MHD) instabilities in the edge pedestal region of tokamak plasmas. ELMs can be detrimental to plasma facing components due to the large transient heat and ion fluxes they may produce, and thus represent a significant challenge for the design and operation of future fusion reactors such as ITER. As a result, interest has grown significantly in obtaining high confinement regimes without ELMs. There has been considerable progress on developing alternatives to the ELMy H-mode regime, such as the quiescent H-mode (QH-mode) and the I-mode. These plasma regimes leverage edge fluctuations and turbulence to maintain a quasi-steady edge plasma without ELMs by generating the extra particle transport needed to relax gradients below typical MHD stability limits. QH-modes and I-modes can operate over broad operational regimes at reactor relevant values of important normalized quantities such as confinement enhancement factors (H98 > 1), ratio of plasma pressure to magnetic pressure (β_t^ped ~ 1% ), and electron collisionality (ν_e^* < 0.1). This talk will focus on overviewing these naturally ELM suppressed regimes and exploring their viability as a candidate regime for future reactors.


Brief Bio: • BS, UC Berkeley 2011, Mechanical and Nuclear Engineering • MS, Georgia Tech 2013, Nuclear and Radiological Engineering (advisor: Professor Stacey) • PhD, Georgia Tech 2016, Nuclear and Radiological Engineering (advisor: Professor Stacey) • Postdoc, MIT Plasma Science and Fusion Center • Recently transitioned to staff research scientist with MIT PSFC, focusing on research edge pedestal physics of tokamak plasmas and scenario development for operating regimes that will be used in future fusion reactors.


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