Performance of a MPD Plasma Source and Magnetic Nozzle for Fusion Propulsion

Marriott, Darin; Mikellides, Pavlos G.; Gregorek, G. M.; Turchi, P. J.

doi:10.2514/6.2002-3934

Cited by 3 publications

(5 citation statements)

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“…A mass-averaged stagnation enthalpy based on MACH2 computed outlet profiles predicts an average stagnation temperature of about 79 eV for operation at a maximum source power of about 175 MW and 6.45 g s −1 . An average electron temperature was computed at the exhaust of the source to be 15.4 eV, once again in relatively good agreement with probe voltage measurements performed experimentally [3] and described in part I of this set of two papers.…”

Section: Plasma Characterizationsupporting

confidence: 76%

“…Despite the upstream evolution of the current for high power operation and the subsequent elevated temperature values in the vicinity of the insulator the source did not demonstrate any ill effects mainly due to the alleviated heat content of the flow at the lower density operation. The average density value at the source's exhaust for the maximum voltage case is computed to about 0.3 kg m −3 , see figure 9, which translates to 0.45 × 10 20 m −3 and it is quite commensurate to the triple probe downstream measurement obtained by the experiment [3] and described in part I of this set of two papers.…”

Section: Plasma Characterizationsupporting

confidence: 65%

“…Through the use of this facility and plasma source, multiple experiments [3] were conducted using helium gas ranging from 1 to 40 g s −1 producing unprecedented source power levels exceeding 180 MW and 300 kA of operating current. These experiments measured quasi-steady current and voltage waveforms, yielding voltage-current characteristics for a wide range of mass-flow rate values.…”

Section: Introductionmentioning

confidence: 99%

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Energy deposition via magnetoplasmadynamic acceleration: II. modeling and performance predictions

Mikellides

England

Gilland

2008

Plasma Sources Sci. Technol.

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A time-dependent, two-dimensional, axisymmetric magnetohydrodynamics code is employed to model, validate and extend the experimentally-limited performance characteristics of a gigawatt-level plasma source that utilized magnetoplasmadynamic (MPD) acceleration for gas energy deposition. Accurate modeling required an upgrade of the code's circuit routines to properly capture the pulse-forming-network current waveform which also serves as the primary variable for validation. Comparisons with experimentally deduced current waveforms were in good agreement for all power levels. The simulations also produced values for the plasma voltage which were compared with the measured voltage across the electrodes. The trend agreement was encouraging while the magnitude of the discrepancy is approximately constant and interpreted as a representation of the electrode fall voltage. Force computations captured the expected electromagnetic acceleration trends and serve as further verification. They also allow examination of the device as a very high power MPD thruster operating at power levels in excess of 180 MW. The computations offer insights into the plasma's characteristics at different power levels through two-dimensional distributions of pertinent parameters and identify design guidelines for effective stagnation temperature values as a function of the mass-flow rate.

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Section: Plasma Characterizationsupporting

confidence: 76%

Section: Plasma Characterizationsupporting

confidence: 65%

Section: Introductionmentioning

confidence: 99%

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Energy deposition via magnetoplasmadynamic acceleration: II. modeling and performance predictions

Mikellides

England

Gilland

2008

Plasma Sources Sci. Technol.

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“…The experiment consists primarily of 'Godzilla', a GW-level LC-ladder energy source [8] and an inverse-pinch switching system previously modified into an MPD plasma source [9]. The design and operation of the component systems and experimental diagnostics are described here.…”

Section: Experimental Facilitymentioning

confidence: 99%

“…The mass injection system for the plasma source was revised from the system used in previous experiments to allow for improved operation in the anticipated magnetic nozzle experiments. The original configuration used a plenum/shocktube injecting gas directly into the interelectrode region [9]. This posed two difficulties for operation of the source at higher mass flow rate.…”

Section: Mass Injection Systemmentioning

confidence: 99%

Energy deposition via magnetoplasmadynamic acceleration: I. Experiment

Gilland

Mikellides

Marriott

2008

Plasma Sources Sci. Technol.

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The expansion of a high-temperature fusion plasma through an expanding magnetic field is a process common to most fusion propulsion concepts. The propulsive efficiency of this process has a strong bearing on the overall performance of fusion propulsion. In order to simulate the expansion of a fusion plasma, a concept has been developed in which a high velocity plasma is first stagnated in a converging magnetic field to high (100s of eV) temperatures, then expanded though a converging/diverging magnetic nozzle. As a first step in constructing this experiment, a gigawatt magnetoplasmadynamic plasma accelerator was constructed to generate the initial high velocity plasma and has been characterized. The source is powered by a 1.6 MJ, 1.6 ms pulse forming network. The device has been operated with currents up to 300 kA and power levels up to 200 MWe. These values are among the highest levels reached in an magnetoplasmadynamic thruster. The device operation has been characterized by quasi-steady voltage and current measurements for helium mass flow rates from 0.5 to 27 g s −1 . Probe results for downstream plasma density and electron temperature are also presented. The source behavior is examined in terms of current theories for magnetoplasmadynamic thrusters.

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