@article{oai:nifs-repository.repo.nii.ac.jp:00011650,
 author = {NESPOLI, Federico and MASUZAKI,  Suguru and TANAKA,  Kenji and ASHIKAWA,  Naoko and SHOJI,  Mamoru and GILSON, Eric and LUNSFORD, Robert and OISHI,  Tetsutarou and OISHI,  Tetsutaro and IDA,  Katsumi and YOSHINUMA,  Mikirou and TAKEMURA,  Yuki and TAKEMURA, Yuuki and KINOSHITA, Toshiki and MOTOJIMA,  Gen and KENMOCHI, Naoki and KAWAMURA,  Gakushi and SUZUKI,  Chihiro and NAGY, Alex and BORTOLON, A. and PABLANT, Novimir and MOLLEN, Albert and TAMURA,  Naoki and GATES, David and MORISAKI,  Tomohiro},
 journal = {Nature Physics},
 month = {Jan},
 note = {0000-0001-7644-751X, In state-of-the-art stellarators, turbulence is a major cause of the degradation of plasma confinement. To maximize confinement, which eventually determines the amount of nuclear fusion reactions, turbulent transport needs to be reduced. Here we report the observation of a confinement regime in a stellarator plasma that is characterized by increased confinement and reduced turbulent fluctuations. The transition to this regime is driven by the injection of submillimetric boron powder grains into the plasma. With the line-averaged electron density being kept constant, we observe a substantial increase of stored energy and electron and ion temperatures. At the same time, the amplitude of the plasma turbulent fluctuations is halved. While lower frequency fluctuations are damped, higher frequency modes in the range between 100 and 200 kHz are excited. We have observed this regime for different heating schemes, namely with both electron and ion cyclotron resonant radio frequencies and neutral beams, for both directions of the magnetic field and both hydrogen and deuterium plasmas.},
 pages = {350--356},
 title = {Observation of a reduced-turbulence regime with boron powder injection in a stellarator},
 volume = {18},
 year = {2022}
}