Register Date 2019-10-29
|Research Achievements||Spontaneous plasma flow generation by symmetry breaking of global electromagnetic ion temperature gradient modes|
|Main Contributor||Helen Kaang|
|Related Research Project||Integrated Modelling of Turbulence and Transport in Tokamak Fusion Plasmas|
|Major Research Achievements||Qualitative Achievements
- Plasma flow (or rotation) has been reported to play an important role in reducing turbulent transport and stabilizing magnetohydrodynamic instabilities. The spontaneous generation of plasma flow is necessary for ITER to achieve a desirable plasma performance. We developed a quasilinear theory based code for the estimation of spontaneous plasma flow generation which is induced by ITG modes.
- We showed that the plasma flow can be enhanced spontaneously with increasing plasma beta(=plasma thermal energy/magnetic energy). This means that enhanced confinement mode aimed by ITER can generate a large plasma flow.
- We suggested a new mechanism for the spontaneous plasma flow generation: the global electromagnetic effects by the increase of plasma beta induce the parity mixing of ITG mode, by which symmetry breaking in ITG mode occurs resulting in the spontaneous flow generation.
- Published in Physics of Plasmas 25, 012505
- Presented as invited talk at 8th Asia Pacific Transport Working Group conference
|Superiorities & differences||Superiorities
- We presented a theoretical basis on the strong generation of plasma flow experimently observed in enhanced confinement mode and the change of plasma flow distribution observed when an additional heating source is applied to the plasma.
- Up until now, most of the studies on the spontaneous flow generation have been performed by considering electrostatic ITG turbulence. In this work, we studied global electromagnetic ITG mode, through which we presented parity mixing in ITG mode by the global electromagnetic effect as a new symmetry breaking mechanism for the spontaneous flow generation.
|Expected Effect &
| Technical Perspectives
- The developed code and newly suggested concept on the spontaneous flow generation is expected to be usefully applicable to the analysis of plasma flow observed in experiments.
Change of Reynolds stress (source of plasma flow generation) with increasing plasma beta