@article{oai:nifs-repository.repo.nii.ac.jp:00010678,
 author = {MUKAI,  Kiyofumi and MASUZAKI,  Suguru and PETERSON,  Byron and PETERSON,  Byron J. and AKIYAMA,  Tsuyoshi and KOBAYASHI,  Masahiro and SUZUKI,  Chihiro and TANAKA,  Hirohiko and PANDYA,  Shwetang N and SANO,  Ryuichi and MOTOJIMA,  Gen and OHNO,  Noriyasu and MORISAKI,  Tomohiko and MURAKAMI,  Izumi and MIYAZAWA,  Junichi and MIYAZAWA, Jun-ichi and TAMURA,  Naoki and YOSHIMURA,  Shinji and YAMADA,  Ichihiro and YASUHARA,  Ryo and FUNABA,  Hisamichi and TANAKA,  Kenji and LHD, Experiment Group},
 issue = {8},
 journal = {Nuclear Fusion},
 month = {Jul},
 note = {0000-0003-1586-1084, Impurity seeding to reduce the divertor heat load was conducted in the large helical device (LHD) using neon (Ne) and krypton (Kr) puffing. Radiation enhancement and reduction of the divertor heat load were observed. In the LHD, the ratio between the total radiated power and the heating power, f rad = Prad/Pheating, is limited up to around 30% in hydrogen plasmas even for high density plasma just below the radiative collapse (ne, bar  >  1   ×   1020 m−3), where ne, bar is the line averaged density. With Ne seeding, the ratio could be raised to 52% at ne, bar ~ 1.3   ×   1019 m−3, albeit with a slight reduction in confinement. f rad ~ 30% could be sustained for 3.4 s using multi-pulse Ne seeding at ne, bar ~ 4   ×   1019 m−3. The localized supplemental radiation was observed along the helical divertor X-points (HDXs) which is similar to the estimated structure by the EMC3-EIRENE code. Kr seeding was also conducted at ne, bar ~ 3.1   ×   1019 m−3. f rad ~ 25% was obtained without a significant change in stored energy. The radiation enhancement had a slower time constant. The supplemental radiation area of the Kr seeded plasma moved from the HDXs to the core plasma. Highly charged states of Kr ions are considered to be the dominant radiators from the plasma core region.},
 title = {Development of impurity seeding and radiation enhancement in the helical divertor of LHD},
 volume = {55},
 year = {2015}
}