banner image
No data available.
Please log in to see this content.
You have no subscription access to this content.
No metrics data to plot.
The attempt to load metrics for this article has failed.
The attempt to plot a graph for these metrics has failed.
Formation of a long-lived hot field reversed configuration by dynamically merging two colliding high-β compact toroidsa)
a)Paper DI3 1, Bull. Am. Phys. Soc. , 104 (2010).
Rent this article for
View: Figures


Image of FIG. 1.
FIG. 1.

(Color online) Schematic of the C-2 facility.

Image of FIG. 2.
FIG. 2.

(Color online) Evolution of the excluded flux radius in C-2 obtained from a series of external diamagnetic loops at the two θ-pinch formation sections and magnetic probes embedded inside the central metal confinement chamber. Time is measured from the instant of synchronized field reversal in the θ pinch sources, and distance is given relative to the center of the confinement chamber.

Image of FIG. 3.
FIG. 3.

(Color online) Contours of electron density (, ) for the single-source (translating) and dual source (collision-merging) FRCs, obtained from a six-channel two-color CO/HeNe interferometry located at the midplane of the central confinement chamber using the Abel inversion technique.

Image of FIG. 4.
FIG. 4.

(Color online) Simulation of FRC formation, translation, and merging dynamics for the same shot as shown in Fig. 2 , i.e., #5512, showing time histories of both magnetic flux and temperature predicted by the 2-D resistive MHD code, LamyRidge. The magnetic reconnection induced by collision is clearly demonstrated by the evolution of the flux contours.

Image of FIG. 5.
FIG. 5.

(Color online) Comparison of the initial translated CTs and the resultant merged FRC, showing time traces of the external poloidal field, , the excluded flux radius, , the poloidal flux, , and the total temperature,  =   +  , derived from radial pressure balance, for individual CTs produced by θ-pinches on the north side and the south side, respectively, and the result from merging individual CTs formed under identical conditions. Note that the two single CTs were not captured by the end mirrors due to their high translation speeds. Merging occurs around 30 μs, as indicated.

Image of FIG. 6.
FIG. 6.

(Color online) Comparison of radial electron temperature profiles, (), obtained from a nine-chord Thomson scattering system for individual plasmoids and merged FRCs.

Image of FIG. 7.
FIG. 7.

(Color online) Ion temperature, , from Doppler spectroscopy and electron temperature, , from Thomson scattering vs total temperature, , derived from radial pressure balance, in merged FRCs.

Image of FIG. 8.
FIG. 8.

(Color online) Effect of dynamic translation speed. The data are obtained right after merging (∼ 40 μs) of the FRCs from a series of reproducible and well-controlled discharges with the same magnetic configurations and gas fuelling rates. The translation speed is varied by energizing the θ-pinch coils at various different times during the initial formation process.

Image of FIG. 9.
FIG. 9.

(Color online) Tomographic reconstruction of bremsstrahlung radiation in the FRC with  = 2 mode, obtained from a 60-chords visible tomography system. Frame (a) was obtained at the onset of the  = 2 mode, and frames (b)–(d) during half cycle of the  = 2 mode, rotating in the ion diamagnetic direction.

Image of FIG. 10.
FIG. 10.

(Color online) (a) Line-integrated density measurements, , from separate channels at different impact parameters of the CO/HeNe interferometer, located at the center of the confinement chamber ( = 0) and fitted results for shot #4047; (b) density profiles during the  = 2 rotation at ∼ 0.5 ms, obtained from the modified RR model.

Image of FIG. 11.
FIG. 11.

(Color online) (a) Fluctuation spectra at the edge, obtained from the reflectometer; (b) line-integrated density, , obtained from the interferometer with a line of sight near the center of the FRC.

Image of FIG. 12.
FIG. 12.

(Color online) Effect of quadrupole stabilization against the  = 2 mode, which can be clearly seen from the amplitude oscillations on the line-integrated density, . Onset of the  = 2 modes also indicated.

Image of FIG. 13.
FIG. 13.

(Color online) Time evolution of plasma rotation frequency, Ω, with and without quadrupole stabilization.

Image of FIG. 14.
FIG. 14.

(Color online) (a) Magnetic flux confinement time of merged FRCs in C-2, , vs the LSX scaling for conventional θ-pinch-formed FRCs, , along with the results from recent FRC translation experiments, FIX 3 , TCS 6 , as well as those obtained on C-2 during the initial start-up phase with only one single θ-pinch formation source attached to the central confinement chamber and a strong magnetic mirror plug at the downstream end to capture the translated FRCs; (b) diffusivities, , derived from , vs classical diffusivities, , for the well-centered merged FRCs in C-2.


Article metrics loading...


Full text loading...

This is a required field
Please enter a valid email address
752b84549af89a08dbdd7fdb8b9568b5 journal.articlezxybnytfddd
Scitation: Formation of a long-lived hot field reversed configuration by dynamically merging two colliding high-β compact toroidsa)