Secondary electron emission and the bifurcation of the heat flux to the targets in fusion plasmas

作者：Lee Wonjae^*; Krasheninnikov Sergei I

来源：Physics of Plasmas, 2013, 20(12): 122501.

DOI：10.1063/1.4835295

The presence of secondary electron emission (SEE) from plasma facing components in fusion devices can result in a strong localization of the heat flux from plasma to the wall and subsequent wall erosion. Usually, the impact of the SEE is considered assuming the Maxwellian distribution of the electrons coming to the surface. As a result, the SEE coefficient only depends on the temperature of primary electrons. However, the tail of primary electron distribution function in the scrape off layer (SOL) of fusion devices can be far from Maxwellian due to preferential loss of fast electrons. Consequently, it is shown that the SEE coefficient will depend on the wall potential and multiple solutions can be possible corresponding to different regimes of plasma flow to the wall: with and without SEE effects. This effect can cause two-slope electron temperature profiles in the SOL, which are often seen in experiments.

• 出版日期2013-12