Long-pulse Plasma Discharges by Upgraded ECH System in the LHD Y. Yoshimura, H. Kasahara, K. Nagasaki, M. Tokitani, N. Ashikawa, Y. Ueda, S. Ito, S. Kubo, T. Shimozuma, H. Igami et al. (12 more) EPJ Web of Conferences, 87 (2015) 02020 Published online: 12 March 2015 DOI: 10.1051/epjconf/20158702020