The PTSX device consists of three cylindrical electrodes with radius , each divided into four 90° sectors. An oscillating voltage confines the plasma in the transverse plane to a radius . Static voltages on the end electrodes confine the ions axially within a length .
Instantaneous changes in the voltage wave form amplitude cause envelope oscillations that result in various amounts of transverse heating, and thus various amounts of radial expansion and corresponding central density decrease.
WARP 2D simulations using the full time-dependent quadrupole field (circles) compare favorably with the experimental data for the 30% increase (triangles) and the 50% increase (squares) in voltage wave form amplitude.
For the baseline case, , , , and . All of the selected points, A through H, have either , 60, or . All of the selected points have one parameter in common with the baseline case. Some selected points are connected by curves of constant or constant .
The measured radial charge profile can be converted into to the radial density profile by dividing by where is the area of the collector and is the length of the plasma column. For simultaneous proportional instantaneous changes in the voltage wave form amplitude and frequency, there is no change in the transverse density profile of the plasma.
The final-state radial charge profile (and, hence, density profile) is independent of whether , , or is kept fixed when is reduced by a factor of 1.5.
When increases and the effective temperature increases as well, then may either increase or decrease as necessary in order to maintain radial force balance. A sudden transition to a large value of leads to a drastic change in the shape and temperature of the plasma.
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