Physics of Plasma Detachment in a Magnetic Nozzle

Deline, Chris; Chavers, Greg; Gilchrist, Brian E.

doi:10.2514/6.2006-4653

Cited by 7 publications

(7 citation statements)

References 8 publications

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“…The Detachment Demonstration EXperiment (DDEX) studies plasma produced by a pulsed plasma washer gun under the influence of a magnetic nozzle. 35,36,38 Detachment is demonstrated, suggesting super-Alfvénic detachment as the driving mechanism. Super-Alfvénic flow, β f > 1, is shown at the detachment location, but field line stretching is not measured.…”

Section: Detachment Demonstration Experimentsmentioning

confidence: 90%

Magnetic Nozzle Plasma Plume: Review of Crucial Physical Phenomena

Ebersohn¹,

Girimaji²,

Staack³

et al. 2012

48th AIAA/ASME/SAE/ASEE Joint Propulsion Conference &Amp;amp; Exhibit

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This paper presents a review of the current understanding of magnetic nozzle physics. The crucial steps necessary for thrust generation in magnetic nozzles are energy conversion, plasma detachment, and momentum transfer. The currently considered mechanisms by which to extract kinetic energy from the plasma include the conservation of the magnetic moment adiabatic invariant, electric field forces, thermal energy directionalization, and Joule heating. Plasma detachment mechanisms discussed include resistive diffusion, recombination, magnetic reconnection, loss of adiabaticity, inertial forces, and self-field detachment. Momentum transfer from the plasma to the spacecraft occurs due to the interaction between the applied field currents and induced currents which are formed due to the magnetic pressure. These three physical phenomena are crucial to thrust generation and must be understood to optimize magnetic nozzle design. The operating dimensionless parameter ranges of six prominent experiments are considered and the corresponding mechanisms are discussed.

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Section: Detachment Demonstration Experimentsmentioning

confidence: 90%

Magnetic Nozzle Plasma Plume: Review of Crucial Physical Phenomena

Ebersohn¹,

Girimaji²,

Staack³

et al. 2012

48th AIAA/ASME/SAE/ASEE Joint Propulsion Conference &Amp;amp; Exhibit

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“…A more detailed description of the experiment configuration for the Demonstration of Detachment Experiment (DDEX) has been presented previously. 11,13 A top view of the experiment is given in Fig. 1.…”

Section: Experiments Setupmentioning

confidence: 99%

Simulation and Measurement of High-Beta Plasma in a Magnetic Nozzle

Deline¹,

Gilchrist

Bengtson

et al. 2007

43rd AIAA/ASME/SAE/ASEE Joint Propulsion Conference &Amp;amp; Exhibit

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“…It was also clarified that the ion acceleration mechanism in the magnetic nozzle was an ambipolar electric field with the result of which the local axial ion speed reaches Mach 4 downstream. To investigate the plasma detachment process downstream, Deline et al 12,13 conducted experiments at NASA Marshall Center using a plasma gun, magnetic nozzle coils, and RF interferometer measurements. It was concluded that with an initially low-beta flow along the magnetic field, detachment occurred when the plasma kinetic pressure approached magnetic pressure values and then there was a high-beta plume expanding afterward.…”

Section: Introductionmentioning

confidence: 99%

Modeling of plasma processes in the slowly diverging magnetic fields at the exit of an applied-field magnetoplasmadynamic thruster

Tang

Ren

et al. 2013

Physics of Plasmas

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The performance of plasma thrusters with applied electric and magnetic fields can be enhanced by increasing the magnetic field strength, which is applied in the thrust chamber and the exit region propulsive plume. The ejected plasma which passes through a slowly diverging magnetic field will expand but can be restricted within the magnetic nozzle fields. To examine in detail the processes that occur, a new method with Particle-in-cell calculations is applied here. A two-dimensional axisymmetric particle dynamic code is used to model an AF-MPDT (Applied-field Magnetoplasmadynamic Thruster) for which extensive experimental data are available; it used Ar propellant and had applied magnetic coils of 101.5 mm radius and 153 mm length. From the results of the simulation study, it is found that total thrust increases linearly with magnetic field strength in the range of 0-0.1 T, but it decreases with increasing applied magnetic field up to 0.6 T. Thrust efficiency is found to increase to a maximum of 8.4% when B ¼ 0.1 T; further, the peak value of nozzle efficiency reaches 91% at a moderate magnetic field (0.3 T). In detail, it is found that distributions of plasma density (10 14 -10 15 m À3 ) that form in the magnetic nozzle demonstrate a significant pattern of concentration up to fields of B ¼ 0.3 T where ions begin to be magnetized. However, azimuthal velocities of ions behave differently with different degrees of magnetization, i.e., weakly magnetized ions follow rotating electrons in a right-handed direction, while fully magnetized ions revolve in left-handed direction due to electromagnetic forces. Notably, a feedback effect on total magnetic field due to plasma motion identified in other studies is not found to be present in the working conditions of the AF-MPDT examined here. V C 2013 AIP Publishing LLC.

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Physics of Plasma Detachment in a Magnetic Nozzle

Cited by 7 publications

References 8 publications

Magnetic Nozzle Plasma Plume: Review of Crucial Physical Phenomena

Magnetic Nozzle Plasma Plume: Review of Crucial Physical Phenomena

Simulation and Measurement of High-Beta Plasma in a Magnetic Nozzle

Modeling of plasma processes in the slowly diverging magnetic fields at the exit of an applied-field magnetoplasmadynamic thruster

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