FIGURE F-2 Optical emissions from an injected neutral puff into the plasma. SOURCE: Courtesy of Robert M. Winglee, University of Washington.

FIGURE F-2 Optical emissions from an injected neutral puff into the plasma. SOURCE: Courtesy of Robert M. Winglee, University of Washington.

improve understanding of the proposed magnetic inflation process and to confirm models of the effect.3,4 These tests included that measurements of the plasma parameters at the helicon source and at the magnetic equator and perturbations in the magnetic field caused by plasma injection along dipole field lines. The tests demonstrated plasma confinement by the M2P2 followed classical linear scaling up to the point where wall effects became important, and the tests demonstrated plasma inflation. This finding was instrumental in leading to NASA evaluation and testing in a much larger chamber.

The Phase I effort developed extensive models for the effect. This modeling was based on the fluid equations for plasmas, but the equations for conservation of mass and energy were combined in a multifluid treatment. This is more complex than traditional MHD modeling, which combines the equations into a single-fluid treatment. The multifluid approach required that the dynamics of the electrons and the different ions species be kept separate. The modeling was detailed and led to the amount of solar wind deflection with dipole tilt and the total force imparted onto the M2P2. On the basis of these detailed calculations and the development of a laboratory prototype, a Phase II award was made.

As part of the NIAC Phase II project, a simulation model5,6 was developed where the magnetic field was represented by either a point dipole or a finite width solenoid and studies were performed to resolve processes occurring in close proximity to the magnet. The modeling was complicated by the physics of wall interactions, observed in the test program, that cause mirror currents, sputtering, and plasma sheaths. These effects were not incorporated into the model due to computational limitations. Despite those limitations, both the modeling and the tests in a 1-m-diameter chamber gave evidence that the M2P2 prototype had proven transport of magnetic flux. Figure F-2 shows quenching of the plasma initially followed by expansion of the closed field lines. The emission extends both downward and further into the chamber as the models predict.

These initial NIAC Phase II tests led to further testing at MSFC in an 18 ft × 32 ft vertical vacuum chamber and used a plasma source from the SEPAC program for comparisons with the M2P2

3

R.M. Winglee, T. Ziemba, J. Slough, P. Euripides, and D. Gallagher, Laboratory testing of Mini-Magnetospheric Plasma Propulsion prototype, p. 407 in 2001 Space Technology and Applications International Forum, M.S. El-Genk, ed., CP552, American Institute of Physics, College Park, Md., 2001.

4

T. Ziemba, R.M. Winglee, and P. Euripides, Parameterization of the laboratory performance of the Mini-Magnetospheric Plasma Propulsion (M2P2) prototype, 27th International Electric Propulsion Conference, October 15-19, 2001.

5

R. Winglee, T. Ziemba, P. Euripides, and J. Slough, Computer modeling of the laboratory testing of Mini-Magnetospheric Plasma Propulsion (M2P2), International Electric Propulsion Conference Proceedings, October 14-19, 2001.

6

R. Winglee, T. Ziemba, P. Euripides, and J. Slough, Computer modeling of the laboratory testing of Mini-Magnetospheric Plasma Propulsion (M2P2), International Electric Propulsion Conference Proceedings, October 14-19, 2001.



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