Accelerated Taylor State Plumes in SSX

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Roger Howard
5 years ago
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Brown Research supported by DOE OFES & ARPA-e ALPHA 24 August 2016

1 Accelerated Taylor State Plumes in SSX Manjit Kaur Swarthmore College, Swarthmore, PA J. E. Shrock 18, J. Han 17, D. A. Schaffner & M. R. Brown Research supported by DOE OFES & ARPA-e ALPHA 24 August 2016 US-Japan Workshop on Compact Tori 2016, Hotel Irvine, Irvine, CA 92614, USA

2 Our goal Twisted Taylor state A magnetic plasma object exhibiting minimum energy state First observed in SSX lab (Gray et al., PRL, 2013) Our goal is to accelerate a Taylor state to high velocity, then stagnate and compress the object into a suitable MIF target 24 August

3 Overview of talk o System description o Un-accelerated SSX plasma o Injected into glass tube with different liners o Baseline velocity, density and temperature o Accelerated SSX plasma o Velocity predictions o Experimental progress o Summary 24 August

4 System schematic 4

5 Un-accelerated Plasma

6 Current set-up 6

7 Velocity Measurements 24 August

8 B probes installed on glass Single turn wire loops Separated by 10 cm each 24 August

9 Time of Flight measurements Time travelled by the structure at different locations 24 August

10 Plume velocity with glass 24 August

11 Resistive flux conserver SS309 foil, thickness ~ 50 μm Magnetic soak time ~ 3 μs 24 August

12 Plume velocity with resistive liner 24 August

13 Mesh flux conserver Bronze mesh, thickness ~ 450 μm, transparency ~ 42% Magnetic soak time ~ 245 μs 24 August

14 Plume velocity with mesh conserver 24 August

15 Density & Temperature measurements 24 August

16 Characterization in expansion chamber Interferometer chord, different chords of IDS and two magnetic probes also shown in the expansion chamber 24 August

17 Density of Taylor plume 24 August

18 16-channel trans-impedance amplifier circuit 24 August

19 Ion temperature Profile 24 August

20 Line shape from glass 24 August

21 Plasma production 24 August

22 Ion temperature of expansion side plasma 24 August

23 Line shape of expansion side plasma 24 August

24 Un-accelerated Taylor state Density cm 3 Mass 25 μg Volume ~15 liters Velocity ~30 km/s Kinetic energy ~10 Joules 24 August

25 o System description o Un-accelerated SSX plasma Overview of talk o Injected into glass tube with different liners o Baseline velocity, density and temperature v = 30 km/s, n cm 3, T i = 30 ev o Accelerated SSX plasma o Velocity predictions o Experimental progress o Summary 24 August

26 Accelerated Plasma

27 Acceleration with single theta pinch coil 24 August

28 Acceleration system capabilities C 1.3 μf (@100 kv) Power supply output voltage Energy stored, E C Acceleration to velocity, v acc 40 kv 1 kj 290 efficiency, v acc 145 km/s 24 August

29 Pulsed theta pinch coil Multiple parallel coaxial cable connections to reduce inductance, L 1 μh τ1 4 LC 1 μsec 24 August

30 Progress Theta pinch coil & stagnation flux conserver are ready to be installed. Assembling the different parts of the Capacitor charging and discharging circuit i.e., Bochkov switches, Ross relay, diodes, resistors, and capacitors and timing modules etc. (Ian Allfrey & Travis Valentine (TAE) are helping us with their useful suggestions) 24 August

plasma to velocities over 200 km/s and to achieve

31 Ultimate goal Four theta pinch coils will be triggered separately & sequentially to accelerate plasma to velocities over 200 km/s and to achieve compressional density over cm 3 24 August

32 Summary Taylor state characterized in new glass extension with a variety of liners, ready for stagnation experiments Theta pinch coil and accelerator test stand (1 20 kv) nearly ready using TAE components 24 August

33 Thank you

Happy New Year 2017 from SSX!

Happy New Year 2017 from SSX! Here s the annual review from SSX for 2016 as well as plans for 2017. The big news this year is the arrival of Dr. Manjit Kaur as the new SSX postdoc as of May 2016. Manjit