|Title||Synergistic effect of nitrogen and hydrogen seeding gases on plasma detachment in the GAMMA 10/PDX tandem mirror|
|Publication Type||Journal Article|
|Year of Publication||2019|
|Authors||N. Ezumi, T. Iijima, M. Sakamoto, Y. Nakashima, M. Hirata, M. Ichimura, R. Ikezoe, T. Imai, T. Kariya, R. Perillo, I. Katanuma, J. Kohagura, R. Minami, T. Numakura, M. Yoshikawa, S. Togo, M.S Islam, M.M Islam, K. Nojiri, A. Terakado, S. Jang, Y. Kinoshita, T. Mikami, S. Yamashita, T. Yoshimoto, T. Hara, A. Hatayama, K. Ichimura, S. Kado, S. Masuzaki, T. Nakano, N. Ohno, S. Sawada, H. Tanaka, A. Tonegawa|
We have investigated the synergistic effect of a combination of various impurity gases and hydrogen gas on plasma detachment of high temperature plasma, equivalent to scrape-off layer plasma of tokamaks in the GAMMA 10/PDX end region, utilizing an open magnetic field configuration. A small puff of an impurity gas (N2, Ne, Ar, Kr, Xe) in combination with a puff of H2 gas is examined to evaluate their synergistic effect on the formation of detached plasma; the following results are obtained. (i) A combination of N2 and H2 puffs showed a clear decrease of electron density and ion flux; (ii) N2 and H2 puffs form a strong density gradient along the axial direction; and (iii) other noble impurity gases showed an insufficient synergistic effect. The new results indicate the possibility of achieving a reliable divertor operation scheme and the importance of a deeper understanding of the H2 and N2 assisted recombination process.
|Alternate Title||Nucl. Fusion|
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