@article{oai:nifs-repository.repo.nii.ac.jp:00000099,
 author = {MIYAZAWA,  Junichi and SAKAMOTO,  Ryuichi and OHDACHI,  Satoshi and KOBAYASHI,  Masahiro and MASUZAKI,  Suguru and MORISAKI,  Tomohiko and SAKAKIBARA,  Satoru and GOTO,  Motoshi and MORITA,  Shigeru and YAMADA,  Ichihiro and NARIHARA,  Kazumichi and FUNABA,  Hisamichi and TANAKA,  Kenji and MICHAEL,  Clive A. and SUZUKI,  Yasuhiro and WATANABE,  Kiyomasa and OHYABU,  Nobuyoshi and YAMADA, Hiroshi and Komori,  Akio and MOTOJIMA,  Osamu and LHD Experimental Group, and LHD Experimental Groups, and the  LHD Experimental Groups, and the LHD Experimental Group,},
 journal = {Plasma and Fusion Research},
 month = {Jan},
 note = {Abrupt flushing of central density occurs in internal diffusion barrier (IDB) plasmas in the Large Helical Device (LHD), where a super dense core (SDC) of the order of 1020 m-3 is formed inside; this event is called “core density collapse (CDC).” CDC must be suppressed as further increase of the central pressure is inhibited. Since CDC is always accompanied by a large Shafranov shift of the plasma center, it has been supposed that mitigation of the Shafranov shift might affect CDC. Vertical elongation of the plasma shape (κ > 1) is effective in mitigating the Shafranov shift, and κ can be controlled with the quadrupole magnetic field BQ. To examine the impact of plasma shape control on CDC, BQ  scan experiment has been performed in the LHD. The large Shafranov shift in IDB plasmas is mitigated by increasing κ. As a result, CDC is suppressed and high central β values of approximately 7% have been achieved in vertically elongated plasmas. The optimum κ varies with the magnetic configuration. Beta gradients greater than those at CDC in the κ = 1 configuration are observed without CDC in vertically elongated plasmas.},
 title = {Abrupt Flushing of High-Density Core in Internal Diffusion Barrier Plasmas and its Suppression by Plasma Shape Control in LHD},
 volume = {Vol.3},
 year = {2008}
}