Joel C. Hosea

Joel C. Hosea, head of the heating and current drive group at Princeton Plasma Physics Laboratory (PPPL), passed away 25 August 2018. He was 79. Joel was a leading advocate and major contributor to the advancement of the physics and practical applications of RF heating and current drive processes, during a research career that has spanned half a century. Joel graduated from Stanford in 1966, was a National Science Foundation postdoctoral associate at CEA Saclay France, and then joined PPPL in 1968. His early work on the Model C-Stellerator delineated the effects of finite electron mass on ion cyclotron wave generation and mode conversion, and the role of wave propagation in the scrape-off layer on frequency-dependent loading measurements.^1,2 Later experimental work with slow and fast ICRF waves as the RF Group Head on the ST tokamak identified mode-converted EBW generation at the upper hybrid layer. His studies on PLT clearly demonstrated the physics of two-ion minority heating and, for the first time,³He minority heating.³ In 1980, he was appointed PLT project head to carry out a diverse RF heating and current drive research program. He played a key role in studies that achieved pure second harmonic ICRF heating, plasma startup with LHCD without inductive OH for the first time, and related studies of rf interactions with fast ions and electrons. In 1987 he was appointed RF ICRF group head on TFTR and managed the development and installation of ICRF antennas by PPPL and ORNL. In 1991 he was appointed TFTR Tokamak Operations Head for D–T on TFTR during the era that pioneered the application of ICRF heating techniques to D–T plasmas, leading to the first 50–50 D–T and second harmonic T ICRF heating experiments. He also studied the antenna interactions with the edge plasma on TFTR. Following the TFTR effort, he joined the NSTX project first as physics operations head, then as a participant in the RF group, and lastly as the RF group leader. He led a number of RF collaborations on C-Mod, DIII-D, EAST, and KSTAR tokamaks. His most recent contributions focused on identifying the mechanism for fast-wave power losses to the edge plasma as a function of wave spectrum and scrape-off-layer properties.^4–6

References

1. J. C. Hosea and R. M. Sinclair, Phys. Rev. Lett. 23, 3 (1969).
2. J. J. Schuss and J. C. Hosea, Phys. of Fluids 18, 727 (1975).
3. J. C. Hosea et al., Phys. Rev. Lett. 43, 1802 (1979).
4. J. C. Hosea et al., Phys. of Plasmas 15, 056104 (2008).
5. R. J. Perkins et al., Phys. Rev. Lett. 109, 045001 (2012).
6. N. Bertelli et al., Nucl. Fusion 54, 083004 (2014).