Interaction of Energetic Ions and Fast Waves in the Large Plasma Device (LAPD)
POSTER
Abstract
In fusion devices, energetic ions are produced by ionization and charge exchange of injected neutral beams, ion cyclotron heating and current-drive, and byproducts of fusion reactions. The study of energetic ions-wave interactions on magnetic-fusion devices (e.g. dominant fast ion power absorption in some NSTX-U scenarios)1 can be challenging due to harsh plasma environments. Doppler-shifted cyclotron resonance through a proton beam was observed to destabilize Alfvén waves on LAPD2, an 18 m long and 1 m diameter cylindrical device, that produces a magnetized plasma (n = 1011-1013 cm-3, Te= 0.1-15 eV)3. The high-repetition rate (0.2-1.0 Hz), good reproducibility, and various 3D diagnostic tools facilitate detailed exploration of energetic ions and fast wave interactions in LAPD. Interaction between a proton beam (2-15 keV, 15 A) and fast waves launched by a single strap RF antenna was studied. Measurements of 3D wave magnetic-field and beam profiles under varieties of conditions are presented, and energetic-ion diffusion in real and velocity space due to resonant interactions is discussed.
1N. Bertelli, et al., Nucl. Fusion 59, p. 086006 (2019)
2S.K.P. Tripathi, et al., Phys. Rev. E 91, 013109 (2015)
3W. Gekelman, et al., Rev. Sci. Instr., 87, 025105 (2016)
1N. Bertelli, et al., Nucl. Fusion 59, p. 086006 (2019)
2S.K.P. Tripathi, et al., Phys. Rev. E 91, 013109 (2015)
3W. Gekelman, et al., Rev. Sci. Instr., 87, 025105 (2016)
Presenters
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Yhoshua Wug
University of California, Los Angeles
Authors
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Yhoshua Wug
University of California, Los Angeles
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Gurleen Bal
University of California, Los Angeles
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Shreekrishna Tripathi
University of California, Los Angeles
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Nicola Bertelli
Princeton University / Princeton Plasma Physics Laboratory, PPPL
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Troy Carter
University of California, Los Angeles