Path: Propulsion/Electric
% Hall thruster efficiency model with random walk
The efficiency decreases over time. The model uses random walk to compute
three efficiencies for the major loss mechanisms:
j, for the ratio of ion currrent to discharge current;
m, for propellant loss due to incomplete ionization;
u, for thrust loss caused by a nonuniform ion energy distribution.
All are modeled using random walk and have the same input data structure.
Type HallThrusterEfficiency for a demo. The demo approximates
the reference.
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Form:
HallThrusterEfficiency; % demo
[etaA,etaM,etaJ,etaU] = HallThrusterEfficiency(d,h)
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Inputs
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d (.) Data structure
m (.) Ionization loss
.eta (1,1) Starting value of efficiency
.sigma (1,1) Standard deviation
.d (1,1) Drift for random walk model
j (.) Current loss
u (.) Distribution loss
h (1,:) Hours of operation
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Outputs
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etaA (1,1) Overall efficiency
etaJ (1,1) Ratio of ion to discharge current
etaM (1,1) Ratio of ionized fuel to neutral
etaU (1,1) Thrust efficiency
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Reference: Shagayda, A., Gorshkov, O., and Tomilin, D., “The Effect of
Wall Erosion on the Performance of Hall Thrusters,”
The 32nd International Electric Propulsion Conference, 09 2011.
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See also: RandomWalkMarkov
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Common: Graphics/Plot2D Math: Probability/RandomWalkMarkov
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