Synergistic effect of nitrogen and hydrogen seeding gases on plasma detachment in the GAMMA 10/PDX tandem mirror

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 a...

Full description

Saved in:
Bibliographic Details
Published in:Nuclear fusion 2019-06, Vol.59 (6), p.66030
Main Authors: Ezumi, N., Iijima, T., Sakamoto, M., Nakashima, Y., Hirata, M., Ichimura, M., Ikezoe, R., Imai, T., Kariya, T., Katanuma, I., Kohagura, J., Minami, R., Numakura, T., Yoshikawa, M., Togo, S., Islam, M.S., Islam, M.M., Nojiri, K., Terakado, A., Jang, S., Kinoshita, Y., Mikami, T., Yamashita, S., Yoshimoto, T., Hara, T., Hatayama, A., Ichimura, K., Kado, S., Masuzaki, S., Nakano, T., Ohno, N., Sawada, S., Tanaka, H., Tonegawa, A., Perillo, R.
Format: Article
Language:English
Subjects:
divertor
hydrogen
N-MAR
nitrogen
plasma detachment
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary: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.
ISSN:0029-5515
1741-4326
DOI:10.1088/1741-4326/ab1a4a