2023/11/15 by Haotian Mao, Mao, Haotian, Yanzeng Zhang +3 · 1 citation
Engineering · Physics and Astronomy · #Atomic and Molecular Physics #FOS: Physical sciences #Laser-induced spectroscopy and plasma #Magnetic confinement fusion research #Plasma Physics (physics.plasm-ph)
paper · pdf · doi:10.48550/arxiv.2311.09396
openalex publication_date 2023/11/15 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
The assimilation of ablated high-Z impurities into the hot surrounding plasma along the magnetic field is investigated by first-principles kinetic simulations. It is found that the assimilated impurity ions, primarily driven by the ambipolar electric force, propagate steadily into the surrounding plasmas. The high-Z impurities in different charge states are mostly aligned due to the strong collisional friction among them so that the averaged impurity ions charge Z is a deciding factor. Such assimilation is led by an impurity front that is behind the cooling front due to a smaller charge-mass-ratio of the impurity ions Z/mI. With the help of a self-similar solution, the speed of the impurity front Us is shown to be primarily set by the hot surrounding plasma temperature T0 with a weak dependence on the pellet plasma temperature, underscoring the collisionless nature of the impurity assimilation process. Specifically, Us∼ √ZT0/mI. The ambipolar-constrained electron conduction flux from the hot plasma is primarily responsible for the collisionless impurity assimilation process.