Page 12 - Jet Outflow and Open Field Line Measurements on C-2U Device

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Stability of Rotational Mode
Hybrid PIC simulations with HYM code (Belova, APS DPP ‘14)
Comparison of end BCs on Er
1.
End-shorting
1. End shorting (Er = 0 at end)
• Spinup to Vθ ~ 0.6 VA
• n=1 tilt mode goes unstable, followed by
n=2 rotational mode 2. Periodic
• All n=1-4 modes stable for high resistivity
• Spinup to Vθ ~ 0.4 VA
• C.f. C-2U CHERS measurement ~ 0.4 VA (D. Osin)
3. Er < 0 biasing (like plasma gun)
• n=1 even mode unstable
• (rarely true in experiment)
• n=2 mode relatively stable
• (usually completely stable in experiment)
|Vn|2

- n=0
- n=1
- n=2
- n=3
- n=4
Biased
2.
Periodic
|Vn|2
|Ji |2
3.
t / tA
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