Plasma Radiation during Transient Events in JET

In the future ITER tokamak, the Plasma-Facing Components (PFCs) will be subject to large power loads during intense transient evens such as disruptions, VDEs, MARFEs and bursts of Edge Localised Modes (ELMs). During JET plasma disruptions, the thermal energy (10MJ) and magnetic energy (20MJ) are lost in form of heat to the plasma-facing components on timescales of less than 1ms and 20ms [1], respectively. Initially, the thermal energy is dissipated in the thermal quench followed by the magnetic energy dissipation in the current quench. During the current quench phase, the energy stored in the poloidal magnetic field is radiated non-uniformly over the first wall surfaces and may significantly contribute to the local power loads onto PFCs. The ELM radiation behaviour has been analysed in detail in the Type I ELMy H-mode regime which is the baseline scenario for operation of ITER in high fusion gains. In present tokamaks, the plasma energy drop normalised to the pedestal energy, DWELM/Wped is typically 3-10% during a Type IELM. A significant part of this energy can be found in form of plasma radiation, located mostly in the divertor region (in the present contribution, it is integrated over ~2ms, which is considerably longer than the ELM target power deposition of several 100ms).
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