Conveners
Multiscale Physics and Instabilities in Burning Plasmas
- Masatoshi Yagi (National Institutes for Quantum and Radiological Science and Technology, Rokkasho Fusion Institute)
One of the challenges in gyro-kinetic shaping study is the impact of reversed magnetic shear to the trapped electron mode (TEM) instability, which can only be handled by global gyro-kinetic simulations with kinetic electron response. The configuration with reversed magnetic shear is widely used in recent experiments since it provides the formation of internal transport barrier (ITB) structures...
The destabilization of toroidal Alfven eigenmodes (TAEs) by alpha particles requires special conditions in current tokamaks, and DT operation of JET provides this rare opportunity [1]. The unambiguous observation of these modes is anticipated to be difficult, and the operation in DT is potentially limited by the availability of tritium and the allowable neutron wall activation, which might...
Recent theoretical and experimental studies have suggested possible effects of microturbulence on Alfven eigenmode (AE) saturation and energetic particle (EP) transport in fusion plasmas. Zonal flows can be nonlinearly generated by, and in turn, suppress both the AE and microturbulence. EP Scattering by the microturbulence can affect phase space dynamics in the nonlinear AE-EP interaction....
The success of burning plasma devices relies on their ability to confine fusion alpha particle products long enough for them to transfer a substantial fraction of their energies to the reacting thermal particles via collisions. It is, therefore, essential to develop efficient and robust capabilities to predict the level of energetic ion losses in tokamak experiments. This work...
Control of Alvfén eigenmodes (AEs) driven by energetic neutral beam injection (NBI) ions in DIII-D is explored with the TGLF-EP+Alpha model. TGFL-EP+Alpha is a reduced model assuming stiff-transport informed by DIII-D experiments and nonlinear gyrokinetic simulations. In DIII-D shot 180625, neutron deficit below classical predictions (a proxy for AE transport of fast ions) is experimentally...
An interface for kinetic stability analysis has been implemented in TRANSP, motivated by recent advances in the calculation of fast ion transport induced by MHD and Alfvénic Eigenmodes [1] in time-dependent simulations and by the need for predicting accurate evolution of fast ion pressure profiles for the interpretation, prediction and design of controlled plasma discharges. Similar efforts...
A thermal ion driven bursting instability with rapid frequency chirping, assessed to be an Alfvénic ion temperature gradient mode [1], has been observed in plasmas having reactor-relevant temperature in the DIII-D tokamak [2] (see the Fig. 1). The modes are excited over a wide spatial range from macroscopic device size to micro-turbulence size and the perturbation energy propagates across...
