Improved ion containment using a ring-cusp ion thruster

Sovey, James S.

doi:10.2514/6.1982-1928

Cited by 19 publications

(19 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It was not possible to create the 0.3 T magnetic fields now found at the pole pieces of some multipole designs. 12 The improved performance of these designs suggests that some redirection of ion currents is indeed occurring. In any case, the uniform ion current distribution of low field strength multipole thrusters is clearly demonstrated here.…”

Section: Existing Thruster Designsmentioning

confidence: 98%

“…Using the density cited previously, Eq. (12) gives an ion current to the side wall of 1010 mA, whereas Eq. (13) gives a current of 40 mA.…”

Section: Other Considerationsmentioning

confidence: 99%

“…If the ions crossed the virtual anode surface with the Bohm velocity, then the current to the side wall would be given by the formula, (12) where n is the plasma density (just cited); e is the charge for singly charged ions in coulombs; A s is the area of the virtual anode surface; and v b is the Bohm velocity corresponding to an electron temperture (T e ) of 5 eV. If, on the other hand, the ion current depends on the ion random thermal velocity, then v) (13) where (14) and Tf is the ion temperature (assumed to be equal to 600 K); k is Boltzmann's constant; and m { is the ion mass.…”

Section: Other Considerationsmentioning

confidence: 99%

See 2 more Smart Citations

The flexible magnetic field thruster

Brophy

Wilbur

1983

Journal of Spacecraft and Rockets

View full text Add to dashboard Cite

The flexible magnetic field thruster is a unique research tool for studying the behavior of direct current electron-bombardment ion thrusters. It utilizes a long wire anode shielded by a circumferential magnetic field. The magnetic field around the anode, which is produced by passing a direct current of up to 150 A through the wire, restricts primary electron flow from the discharge plasma to the anode. Different magnetic field configurations (divergent, cusped, multipole, etc.) can be created by routing the anode wire in various ways through the discharge chamber. The thruster is also designed so ion currents to various internal surfaces can be measured directly. This allows the determination of the distribution of ion currents within the discharge chamber. Experiments indicate that the distribution of ion currents is strongly dependent on the shape and strength of the magnetic field but independent of the discharge current, discharge voltage, and neutral flow rate. Measurements of the energy cost per plasma ion indicate that this cost decreases with increasing magnetic field strength due to increased anode shielding from the primary electrons. Energy costs per argon plasma ion as low as 50 eV were measured. The energy cost per beam ion was found to be a function of the energy cost per plasma ion, extracted ion fraction, and discharge voltage. Part of the energy cost per beam ion goes into creating many ions in the plasma and then extracting only a fraction of them into the beam. The rest of the energy goes into accelerating the remaining plasma ions into the walls of the discharge chamber. Measurement of ion fluxes across a virtual anode surface appears to indicate that ions cross this surface with velocities approaching their random thermal velocity rather than the Bohm velocity. NomenclatureA =area, m 2 B = magnetic flux density, T E = electron energy, eV e = electronic charge, C / = extracted ion fraction J = current, A k = Boltzmann's constant = 1.38 x 10~2 3 J/K m =mass, kg n -plasma density, m~3 P = specific power, eV/ion r = radial position, m T = temperature, K v = velocity, m/s V = voltage, V ju 0 = permeability constant = 1.26 x 10 ~6 H/m Subscripts B =beam b = Bohm back = back surface of discharge chamber D = discharge E= emission e = electron / = magnetic field / = ion P = production or plasma S = virtual anode surface side = side surface of discharge chamber screen = screen grid w = all thruster cathode potential surfaces

show abstract

Section: Existing Thruster Designsmentioning

confidence: 98%

“…Using the density cited previously, Eq. (12) gives an ion current to the side wall of 1010 mA, whereas Eq. (13) gives a current of 40 mA.…”

Section: Other Considerationsmentioning

confidence: 99%

Section: Other Considerationsmentioning

confidence: 99%

See 1 more Smart Citation

The flexible magnetic field thruster

Brophy

Wilbur

1983

Journal of Spacecraft and Rockets

View full text Add to dashboard Cite

show abstract

“…Recent development work on ion engine technology (Sovey 1982a, Rawlin 1982, and Sovey 1982b has focused on the use of noble gas propellants to circumvent the toxicity and spacecraft contamination issues presented by the use of mercury propellant. Our model, based partially upon a model created by Brophy et al (1989), is designed to reflect both theoretical performance predictions and laboratory data collected from ion engine tests.…”

Section: Electron Bombardment Ion Thrustermentioning

confidence: 99%

Electric thruster models for multimegawatt nuclear electric propulsion mission design

Leifer

Blandino

Sercel

1991

AIP Conference Proceedings

View full text Add to dashboard Cite

Three types of electric thrusters currently under development at JPL have potential to support future missions which utilize multimegawatt nuclear elecUic propulsion. These electric thrusters are the electron bombardment ion thruster, the magnetoplasmadynamic (MID) thruster, and the electron-cyclotron-resonance (ECR) thruster. The electron bombardment ion thruster is a relatively mature technology which has been developed for operation at kilowatt power levels but will require new development for application in the multimegawatt regime. The MPD engine represents a technology which may be very well suited to steady-state multimegawatt applications but which has been limited to sub-scale (100's ofkW) and pulsed (MW) testing thus far. The ECR plasma engine represents a class of very promising new concepts which are still in the basic research phase of development, but which may possess important fundamental advantages over other electric thruster technologies. In this paper, models of these thrusters are described and used to make projections of thruster specific mass, efficiency, and power handling capacity for operation in the multimegawatt regime.

show abstract

“…This parameter, which is proportional to the neutral density in the discharge chamber is defined by the expression m(\ -rj u ) where m is the propellant flow rate into the thruster and r/ M is the propellant utilization efficiency. It has been shown by Brophy 2 that the plasma ion energy cost is related to the neutral density parameter by the equation (3) In this equation the parameter e*, the baseline plasma ion energy cost, is the average energy required to produce an ion at high neutral densities. When the neutral density is sufficiently high, primary electrons are not lost directly to the anode, and the only losses associated with ion production are those related to atomic excitation reactions and Maxwellian electron energy losses to the anode.…”

mentioning

confidence: 99%

Ring cusp discharge chamber performance optimization

Hiatt

Wilbur

1986

Journal of Propulsion and Power

View full text Add to dashboard Cite

An experimental study of the effects of discharge chamber length and the location of the anode, cathode, and magnetic field ring cusp within the chamber on the performance of an 8-cm-diam ring cusp thruster is described. Performance changes are measured in terms of plasma ion energy costs, extracted ion fractions, and ion beam profiles. Results show that the anode may be positioned at any location along an "optimum virtual anode" magnetic field line, and minimum plasma ion energy costs will result. The actual location of this field line is related to a "virtual cathode" magnetic field line that is defined by the cathode position. The magnetic field has to be such that the virtual anode field line intersects the grids at the outermost ring of grid holes to maximize the extracted ion fraction and the ion beam profile flatness. Discharge chamber lengths that were as small as possible in the test apparatus yielded the highest extracted ion fractions.

show abstract

Improved ion containment using a ring-cusp ion thruster

Cited by 19 publications

References 2 publications

The flexible magnetic field thruster

The flexible magnetic field thruster

Electric thruster models for multimegawatt nuclear electric propulsion mission design

Ring cusp discharge chamber performance optimization

Contact Info

Product

Resources

About