PHYSICS/BK21 SEMINAR[4.8]

“ Innovative 2D visualization of the critical physics on KSTAR “

* Speaker : Dr. Gunsu Yun [POSTECH]

* Place : Physics Seminar Room (Science Bldg, 3-201)

* Date & Time : Apr, 8 (Thu)  4:00 ~ 5:00 pm

ABSTRACT:

The tokamak concept of magnetic confinement of hot plasmas has been the most promising candidate for sustained thermonuclear fusion, i.e. the future ultimate energy source which will be demonstrated through the ITER project. The ITER design assured by empirically well verified scaling laws has little doubt about achieving its primary goal, i.e., sustainment of the fusion grade plasmas. However, its long-term reliable operation depends upon unresolved scientific and technical issues. The most important scientific challenges are (1) Disruptive behavior, which is rare but can be detrimental for ITER and DEMO operation (2) Loss of alpha particles enhanced through Alfven wave activities, which can prevent reheating of the core plasma. First-principles understanding of the underlying physics of disruption and wave-particle interaction is essential to improve the stability of the fusion grade plasmas. 2D localized measurements of the instabilities and waves, as opposed to the traditional 1D or chordal tomographic measurements, are considered essential for the physics study of complex behaviors in the tokamak plasmas. Postech plasma physics group has participated development of a 2D imaging diagnostic in major tokamaks around the world (DIII-D in US and ASDEX in MPI, Germany) and is developing a similar but advanced system for KSTAR, a unique steady state tokamak that can extend the present short pulse operation to steady state operation. The 2D imaging diagnostic measures electron temperature based on Electron Cyclotron Emission (ECE) from electrons gyrating around the strong magnetic fields. Several preliminary but important discoveries have already been made, including the first observation of intermittent incomplete internal energy transport and direct 2D visualization of Alfven eigenmodes. Potential new physics that can be studied using the ECE imaging system in KSTAR is discussed in detail.

문의처: 박현거(054-279-2096, hyeonpark@postech.ac.kr)