April 4-6

Abstract Details

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Author: Chen Zhao
Requested Type: Consider for Invited
Submitted: 2022-03-04 01:06:23


Contact Info:
100 Stellarator Rd
Princeton, NJ   08540
United States

Abstract Text:
Disruption is a phenomenon that the current suddenly dropped to 0 in tokamak. That is a severe problem we need to resolve. Runaway electron plateau is a mechanism which prevent the current drops down too fast and has been found in many tokamak experiment shots. But the detail of the runaway electron current plateau still needed more research. To predict the occurrence and consequences of runaway generation during a disruption, we have developed a runaway electron module for the M3D-C1 code. The code is a 3D extended magnetohydrodynamics (MHD) simulation code with fluid runaway electron model fully coupled to the bulk plasma. It utilizes an implicit time advance with sub-cycling that allows runaway velocities approaching the speed of light, c. Both the Dreicer and avalanche runaway electron source terms are included. We have verified their implementation by performing benchmarks with the JOREK code, another code widely used in disruption simulation. Our recent result on modeling runaway electron plateau formation during mitigation experiments on DIII-D, including the intentional shedding of runaways by lowering the edge safety factor q(a) (safety factor at tokamak edge) to 2.0, also provides detailed global runaway current, temperature structure with pellet injection which lack of study in previous works.