@article{6140, author = {N. Noda and Y. Nakamura and Y. Takeiri and T. Mutoh and R. Kumazawa and M. Sato and K. Kawahata and S. Yamada and T. Shimozuma and Y. Oka and A. Iiyoshi and R. Sakamoto and Y. Kubota and S. Masuzaki and S. Inagaki and T. Morisaki and H. Suzuki and N. Ohyabu and K. Adachi and K. Akaishi and N. Ashikawa and H. Chikaraishi and P. C. de Vries and M. Emoto and H. Funaba and M. Goto and S. Hamaguchi and K. Ida and H. Idei and K. Ikeda and S. Imagawa and N. Inoue and M. Isobe and A. Iwamoto and S. Kado and O. Kaneko and S. Kitagawa and K. Khlopenkov and T. Kobuchi and A. Komori and S. Kubo and Y. Liang and R. Maekawa and T. Minami and T. Mito and J. Miyazawa and S. Morita and K. Murai and S. Murakami and S. Muto and Y. Nagayama and H. Nakanishi and K. Narihara and A. Nishimura and K. Nishimura and A. Nishizawa and T. Notake and S. Ohdachi and M. Okamoto and M. Osakabe and T. Ozaki and R. O. Pavlichenko and B. J. Peterson and A. Sagara and K. Saito and S. Sakakibara and H. Sasao and M. Sasao and K. Sato and T. Seki and M. Shoji and H. Sugama and K. Takahata and M. Takechi and H. Tamura and N. Tamura and K. Tanaka and K. Toi and T. Tokuzawa and Y. Torii and K. Tsumori and K . Y. Watanabe and T. Watanabe and T. Watari and N. Yanagi and I. Yamada and H. Yamada and S. Yamaguchi and S. Yamamoto and T. Yamamoto and M. Yokoyama and Y. Yoshimura and I. Ohtake and R. Akiyama and K. Haba and M. Iima and J. Kodaira and K. Tsuzuki and K. Itoh and K. Matsuoka and K. Ohkubo and S. Satoh and T. Satow and S. Sudo and S. Tanahashi and K. Yamazaki and O. Motojima and Y. Hamada and M. Fujiwara}, title = {Experimental studies towards long pulse steady state operation in LHD}, abstract = {In the Large Helical Device, stable discharges lasting longer than one minute have been obtained using the complete heating scheme, including ECH. The plasma is sustained with NBI or ICRF of 0.5-1 MW. The central plasma temperature is higher than 1.5 keV with a density of (1-2) x 10(19) m(-3) maintained until the end of the pulse. Full installation of the carbon divertor has contributed to this achievement. This provides a sufficient basis for physics and technology studies for the next campaign. Long pulse operation opens new possibilities in diagnostics and in physics studies. Higher accuracy and reliability are obtained with a diagnostics parameter scan, longer integration of signals or two dimensional measurement. The mechanism of a slow oscillation called 'breathing' is discussed. Hydrogen recycling analysis has been carried out and preliminary results have been obtained. On the basis of these results, the future programme is divided into two categories: (i) physics and technology experiments utilizing long pulse discharges lasting up to 5 minutes, and (ii) extension of the pulse length up to one hour.}, year = {2001}, journal = {Nuclear Fusion}, volume = {41}, number = {6}, pages = {779-790}, month = {Jun}, isbn = {0029-5515; 1741-4326}, doi = {10.1088/0029-5515/41/6/314}, language = {eng}, }