On Current Drive in Field-Reversed Configurations

Clemente, R. A.

doi:10.1143/jpsj.67.3450

Cited by 13 publications

(15 citation statements)

References 7 publications

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“…Thus, differently from Schmit and Fisch, 9 we will focus our attention on the electron fluid only, also because is easier for the electrons to carry the current. [24][25][26]…”

Section: Approachmentioning

confidence: 99%

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Propulsive performance of a finite-temperature plasma flow in a magnetic nozzle with applied azimuthal current

2014

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The plasma flow in a finite-electron-temperature magnetic nozzle, under the influence of an applied azimuthal current at the throat, is modeled analytically to assess its propulsive performance. A correction to the nozzle throat boundary conditions is derived by modifying the radial equilibrium of a magnetized infinite two-population cylindrical plasma column with the insertion of an external azimuthal body force for the electrons. Inclusion of finite-temperature effects, which leads to a modification of the radial density profile, is necessary for calculating the propulsive performance, which is represented by nozzle divergence efficiency and thrust coefficient. The solutions show that the application of the azimuthal current enhances all the calculated performance parameters through the narrowing of the radial density profile at the throat, and that investing power in this beam focusing effect is more effective than using the same power to pre-heat the electrons. The results open the possibility for the design of a focusing stage between the plasma source and the nozzle that can significantly enhance the propulsive performance of electron-driven magnetic nozzles. V

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“…Thus, differently from Schmit and Fisch, 9 we will focus our attention on the electron fluid only, also because is easier for the electrons to carry the current. [24][25][26]…”

Section: Approachmentioning

confidence: 99%

“…To allow a direct comparison, we scale the density profile such that the mass flow rate into the MN is constant with varyingX. Denoting the density profile at the MN throat asñ t ðr;XÞ, this may be written symbolically as n t ðr;XÞ ¼ qðXÞñ t ðr; 0Þ; (24) where the scaling factor can be found from…”

Section: B Density Profile Scalingmentioning

confidence: 99%

Propulsive performance of a finite-temperature plasma flow in a magnetic nozzle with applied azimuthal current

2014

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“…The 1 term arising from the B component has been noted in previous work. [19][20][21] Since int ϰ͉B r ͉ 2 /8 it might be imagined that this is a pressure effect from the RMF. In fact it is not because it does not arise from a pressure gradient, i.e., "͉B r ͉ 2 /8.…”

Section: E Quasisteady Behaviormentioning

confidence: 99%

“…This can also be done by generating a second RMF field, as was proposed by Clemente. 20 If effective, this would involve a negligible complication to RMF current drive since the same antenna structure could be used to drive both the RMF signal for the electrons and the signal for the ions.…”

Section: Other Ion Momentum Sourcesmentioning

confidence: 99%

Transient and quasisteady behavior with rotating magnetic field current drive

Steinhauer

2001

Physics of Plasmas

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The time-dependent behavior of rotating magnetic field (RMF) current drive is investigated using a two-fluid model. The important new factor is the addition of transverse ion mobility in contrast to rigid-ion models of the past. The equations simplify conveniently, allowing the behavior on each surface (r=const) to be isolated, which permits a quadrature solution for the ion fluid rotation. A rapid transient phase leads to quasisteady behavior that evolves on the relatively slow diffusion timescale. The fast transient timescale is set by the ion inertia. Unless there is an ion momentum source to balance the electron drag on the ion fluid, there is no quasisteady current drive effect. Collisions with neutrals offer such a momentum source in some experiments, notably rotamaks and the Star Thrust Experiment. Other sources of ion momentum are essential for RMF current drive in hotter, fusion-relevant plasmas. The properties of the quasisteady state are found, including the self-consistent ion fluid rotation rate and radial electric field, and RMF corrections on the pressure balance.

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“…6 In this scheme one of the RMF should be clamped to the electrons and the other to the ions, in such a way that the individual torques due to collisions can be balanced by the ponderomotive torques arising from the average Lorentz forces due to longitudinal oscillating current densities in the plasma column.…”

Section: Introductionmentioning

confidence: 99%

Electron inertial effects on rotating magnetic field current drive

2006

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The effect of finite electron mass on the formation and sustainment of a field reversed configuration (FRC) by rotating magnetic fields (RMF) is studied. The importance of inertial effects is measured by the ratio between the RMF frequency (ω) and the electron-ion collision frequency (ν). In the limit where this ratio is very small (ω∕ν→0), previous results corresponding to massless electrons are recovered. When ω∕ν increases there are significant changes in the value of the minimum external rotating field needed to sustain the FRC and the time required to reach a steady state. Since ν decreases with increasing temperature and decreasing density, these effects are expected to become more important as fusion relevant temperatures are approached.

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On Current Drive in Field-Reversed Configurations

Cited by 13 publications

References 7 publications

Propulsive performance of a finite-temperature plasma flow in a magnetic nozzle with applied azimuthal current

Propulsive performance of a finite-temperature plasma flow in a magnetic nozzle with applied azimuthal current

Transient and quasisteady behavior with rotating magnetic field current drive

Electron inertial effects on rotating magnetic field current drive

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