Page 4 - Overview of TAE technologies’ HHFW project on LAPD

the direction of fast wave propagation; wave length becomes shorter when edge density ne is in the range of 2.0 ×1018 m-3 ~ 2.8×1018 m-3, which seems to be the nonset density for perpendicular fast wave propagation.
FIGURE 4. Measured HHFW magnetic field pattern (1800 phasing) in x-y plane at different antenna positions.
FIGURE 5. Measured HHFW magnetic field pattern in x-z plane at different phasing. Antenna is at r = -25 cm. FUTURE PLAN
For simulations, RF SciDAC team starts 3D full wave modeling with the Petra-M code [6], which is a newly developed generic electromagnetic simulation tool for modeling RF wave propagation; direct comparison of HHFW magnetic fields obtained from 3D simulations with B-dot probe measurements is on the way. Meanwhile, TAE theory group currently works on expanding TAE’s RF_Pisa code [7] for HHFW regime; validating HHFW modeling results against the experimental measurements is also planned.
For experiments, the following RF campaigns are planned in series on LAPD: (1) wave propagation study at 30 MHz, 2.5 kG; (2) wave coupling studies at both 10 MHz and 30 MHz with a matching network for arbitrary phasing and a wide range of loads; (3) wave coupling and propagation studies at different magnetic configuration (mirror and/or cusp); (4) RF sheath and heating studies at high power (4 × 200 kW) operations.
ACKNOWLEDGMENTS
We would like to acknowledge the support and contributions from the rest of the TAE team and collaborators. A debt of gratitude is also due to our shareholders for their continuous support.
REFERENCES
1. X. Yang, et al., EPJ Web of Conferences 157, 03065 (2017).
2. M. Ono, Phys. Plasmas, 11, 4075(1995).
3. J. Hosea, et al., Phys. Plasmas, 15, 056104 (2008).
4. G. Taylor, et al., Phys. Plasmas, 17, 056114 (2010).
5. W. Gekelman, et al., Rev. Sci. Instr., 87, 025105 (2016).
6. S. Shiraiwa, et al., EPJ Web of Conferences 157, 03048 (2017).
7. F. Ceccherini, et al., Bull. Am. Phys. Soc. 55, GP8.00044 (2013).
300 Phasing 450 Phasing 600 Phasing 900 Phasing 1800 Phasing
Denser plasma
070002-4
r= -15 cm
r= -20 cm
r = -25 cm
r = -30 cm
r= -35 cm