Measurements of secondary electron emission effects in the Hall thruster discharge

Raitses, Yevgeny; Smirnov, A.; Staack, David; Fisch, Nathaniel J.

doi:10.1063/1.2162809

Cited by 86 publications

(48 citation statements)

References 34 publications

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“…In Hall thrusters the electron energies range from 15 eV to 20 eV . Most of the ceramics used to make the thruster walls (BN, SiO 2 , Al 2 O 3 ) at these energies have χ ∼ 1, while the classical Debye layer seems to disappear and the sheath are space charge saturated(SCS) [24]. The charge saturated sheath has been validated recently by both numerical and experimental methods [25,26].…”

Section: Numerical Modelmentioning

confidence: 98%

The Effect of Magnetic Mirror on Near Wall Conductivity in Hall Thrusters

Liu

Cao

et al. 2008

Contrib. Plasma Phys.

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The effect of magnetic mirror on near wall conductivity is studied in the acceleration region of Hall thrusters. The electron dynamics process in the plasma is described by test particle method, in which electrons are randomly emitted from the centerline towards the inner wall of the channel. It is found that the effective collision coefficient, i.e. the rate of electrons colliding with the wall, changes dramatically with the magnetic mirror effect being considered; and that it decreases further with the increase of magnetic mirror ratio to enhance the electron mobility accordingly. In particular, under anistropic electron velocity distribution conditions, the magnetic mirror effect becomes even more prominent. Furthermore, due to decrease in magnetic mirror ratio from the exhaust plane to the anode in Hall thrusters, the axial gradient of electron mobility with magnetic mirror effect is greater than without it. The magnetic mirror effects on electron mobility are derived analytically and the results are found in agreement with the simulation.

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Section: Numerical Modelmentioning

confidence: 98%

The Effect of Magnetic Mirror on Near Wall Conductivity in Hall Thrusters

Liu

Cao

et al. 2008

Contrib. Plasma Phys.

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“…The secondary electron emission influences strongly the electron temperature and the axial conductivity into the channel (the phenomenon known as near-wall conductivity NWC [4]). In fact, it was shown experimentally that the channel wall material has substantial effect on the discharge behavior [5].…”

Section: Stationary Plasma Thrusters (Spts)mentioning

confidence: 99%

Particle‐in‐Cell Simulations for Ion Thrusters

Schneider¹,

Matyash

Kalentev

et al. 2009

Contrib. Plasma Phys.

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The Particle-in-Cell (PIC) method was used to study two different ion thruster concepts: Hall Effect Thrusters (HETs) and High Efficiency Multistage Plasma Thrusters (HEMPs), in particular the plasma properties in the discharge chamber due to the different magnetic field configurations. Special attention was paid to the simulation of plasma particles fluxes on the thrusters inner surfaces. In both cases PIC proved itself as a powerful tool, delivering important insight into the basic physics of the different thruster concepts. The simulations demonstrated that the new HEMP thruster concept allows for a high thermal efficiency due to both minimal energy dissipation and high acceleration efficiency. In the HEMP thruster the plasma contact to the wall is limited only to very small areas of the magnetic field cusps, which results in much smaller ion flux to the thruster channel surface as compared to HET.

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“…predicted to have shorter life times and lower throughput capabilities. The poorer performance of thrusters using alternative materials has been largely attributed to the higher secondary yield [13][14][15] or higher conductivity of these materials compared to the standard BN.…”

Section: Introductionmentioning

confidence: 99%

Conducting Wall Hall Thrusters

Goebel

Hofer

Mikellides

et al. 2013

49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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A unique configuration of the magnetic field near the wall of Hall thrusters, called "magnetic shielding", has recently demonstrated the ability to significantly reduce the erosion of the boron nitride (BN) walls and extend the life of Hall thrusters by orders of magnitude. The ability of magnetic shielding to minimize interactions between the plasma and the discharge chamber walls has for the first time enabled the replacement of insulating walls with conducting materials without loss in Hall thruster performance. The boron nitride rings in the 6 kW H6 Hall thruster were replaced with graphite that self-biased to near the anode potential during operation. The thruster efficiency remained over 60% (within two percent of the baseline BN configuration) with a small decrease in thrust and increase in Isp typical of magnetically shielded Hall thrusters. The graphite wall temperatures decreased significantly compared to both shielded and unshielded BN configurations, leading to the potential for higher power operation. Eliminating ceramic walls makes it simpler and less expensive to fabricate a thruster to survive launch loads, and the graphite discharge chamber radiates more efficiently which increases the power capability of the thruster compared to conventional Hall thruster designs. Nomenclature g = acceleration of gravity Isp = specific impulse ! ˙ m p = total propellant mass flow rate T = thrust P T = Total input power P d = Discharge power P mag = Power into the magnets

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Measurements of secondary electron emission effects in the Hall thruster discharge

Cited by 86 publications

References 34 publications

The Effect of Magnetic Mirror on Near Wall Conductivity in Hall Thrusters

The Effect of Magnetic Mirror on Near Wall Conductivity in Hall Thrusters

Particle‐in‐Cell Simulations for Ion Thrusters

Conducting Wall Hall Thrusters

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