Experimental study of equilibrium in a bumpy torus

Hiroe, S.; Cobble, J. A.; Colchin, R.J.; L., Chen, G.; Connor, K. A.; Goyer, J.R.; Solensten, L.

doi:10.1063/1.865630

Cited by 5 publications

(12 citation statements)

References 9 publications

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“…At still lower pressure, potential contours remained nested, but the The machine axis was located at z = x = 0 and the magnetic axis was at z = 0, x = -2.5 cm (Fig. 2 of Ref [9]).…”

Section: The Operating Regime and Parameters Of Ebtmentioning

confidence: 99%

“…The majority of the warm particles were mirror trapped. These warm electrons were generated when the ambient pressure was below that of the T-C transition and signalled the formation of centrally nested potential contours [9]. The non-Maxwellian distribution function was driven by the ECH heating power.…”

Section: The Operating Regime and Parameters Of Ebtmentioning

confidence: 99%

“…Thus, there was a definite pressure at which the transition from the C-mode to the T-mode occurred. Figures 2(b) to (e) show the potential contours for pressure variations in the vicinity of the transition pressure [9]. For a pressure of 32 /xtorr (deep C-mode), the potential contours were open streamlines, which is the classical non-equilibrium state of a toroidal system without rotational transform.…”

Section: The Operating Regime and Parameters Of Ebtmentioning

confidence: 99%

“…For example, the power incident on the limiter increased as the fluctuation level increased. [7,9,10,13,14,17] Much of the crucial physics of EBT plasmas can be determined from an examination of the 2-D potential contours [31 ] displayed in Fig. 2.…”

Section: Stability Of the Bulk Plasmamentioning

confidence: 99%

“…(1) Plasma potential contours in the C-mode (high ambient pressure) were streamlines, which is the classical non-equilibrium (i.e. non-force-balanced) state of a toroidal confinement system [9]. In contrast to this, central potential contours in the T-mode (lower ambient pressure) were nested, implying that particles were confined.…”

Section: Introductionmentioning

confidence: 99%

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Summary of ELMO Bumpy Torus (EBT-S) experiments from 1982 to 1984

et al. 1988

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Experiments were conducted in the ELMO Bumpy Torus (EBT) from 1973 until 1984. A number of papers have been published concerning various aspects of experiments during the final two years of operation. The paper summarizes the final experimental conclusions and discusses those issues which remain unresolved. The main conclusions are as follows: (1) measurements of the width of the hot electron rings showed them to be wider than previously suspected, diluting their diamagnetism and negating their ability to locally reverse the magnetic field gradient; (2) two-dimensional plots of the plasma potential revealed open potential contours in the C-mode and closed potential contours near the plasma centre in the T-mode; (3) an in–out asymmetry in the plasma potential was always observed, giving rise to electric fields which drove convective plasma loss.

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“…At still lower pressure, potential contours remained nested, but the The machine axis was located at z = x = 0 and the magnetic axis was at z = 0, x = -2.5 cm (Fig. 2 of Ref [9]).…”

Section: The Operating Regime and Parameters Of Ebtmentioning

confidence: 99%

Section: The Operating Regime and Parameters Of Ebtmentioning

confidence: 99%

Section: The Operating Regime and Parameters Of Ebtmentioning

confidence: 99%

Section: Stability Of the Bulk Plasmamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Summary of ELMO Bumpy Torus (EBT-S) experiments from 1982 to 1984

et al. 1988

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Convective contributions to local power loss in a bumpy torus

Hiroe

Haste

Tolliver

et al. 1987

The Physics of Fluids

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Power flow in the ELMO Bumpy Torus [Plasma Physics and Controlled Nuclear Fusion Research, 1974, Tokyo (IAEA, Vienna, 1975), Vol. 2, p. 141; Plasma Phys. 25, 597 (1983)] was investigated by measuring the power received by a limiter. This power was found to be a small fraction of the gyrotron output power (in one case, 13 out of 100 kW). To investigate the reason for the small fraction that appeared on the limiter, power was selectively removed from various cavities, including the cavity containing the limiter. These experiments have demonstrated that the majority of the power is lost locally. Observations of the potential structure demonstrate that asymmetric potential contours are present that can lead to enhanced plasma loss.

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Effect of electric fields and fluctuations on confinement in a bumpy torus

Hiroe

Glowienka

Hillis

et al. 1987

The Physics of Fluids

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In order to understand the relationships between confinement and space potential (electric field) and between confinement and density fluctuations, plasma parameters in the ELMO Bumpy Torus Scale (EBT-S)[in Plasma Physics and Controlled Nuclear Fusion Research (IAEA, Tokyo, 1974), Vol. 2, p. 141; Plasma Phys. 25, 597 (1983)] have been measured systematically for a wide range of operating conditions. Present EBT plasma parameters do not show a strong dependence on the potential profile, but rather exhibit a correlation with the fluctuations. The plasma pressure profile is found to be consistent with the profile anticipated on the basis of the flute stability criterion for a marginally stable plasma. For a heating power of 100 kW, the stored energy density is found to be restricted to the range between 4.5×1013 eV-cm−3 and 7×1013 eV-cm−3. The lower limit remains constant regardless of heating power and pertains to plasmas lacking an equilibrium and/or stability. The upper limit increases with heating power and is found to result from the onset of instabilities. In between the two limits is a plasma that is in an equilibrium state and is marginally stable. Operational trajectories exist that take the EBT plasma from one limit to the other.

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Experimental study of equilibrium in a bumpy torus

Cited by 5 publications

References 9 publications

Summary of ELMO Bumpy Torus (EBT-S) experiments from 1982 to 1984

Summary of ELMO Bumpy Torus (EBT-S) experiments from 1982 to 1984

Convective contributions to local power loss in a bumpy torus

Effect of electric fields and fluctuations on confinement in a bumpy torus

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