Density limit in helicon discharges

Miljak, D.G.; Chen, Francis F.

doi:10.1088/0963-0252/7/4/011

Cited by 44 publications

(37 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The normalizations ω ′ = ω/ω ci , noted, that in helicon discharges the so-called neutral-pumping effect [37,38] is suggested to cause a depletion of neutrals in the plasma center, which in the present study is not taken into account for the estimation of the neutral density. which is not very pronounced due to strong collisional damping of the L-wave indicated by a minimum of the damping length λ d at ω/ω He ci = 0.1 (Fig.…”

Section: Alfvén Waves In Multi-component Plasmasmentioning

confidence: 78%

Alfvén wave dispersion behavior in single- and multicomponent plasmas

et al. 2010

View full text Add to dashboard Cite

Section: Alfvén Waves In Multi-component Plasmasmentioning

confidence: 78%

Alfvén wave dispersion behavior in single- and multicomponent plasmas

et al. 2010

View full text Add to dashboard Cite

“…A similar phenomenon was reported in an experiment which employed two antennas to increase the deposited power. 8 Again, the regions of plasma with the highest ionization rates were also the regions with the highest transport, which limited the overall achievable density.…”

Section: Previous Workmentioning

confidence: 99%

“…12 Measurements from within the expansion chamber ( Figure 6) were obtained by injecting the laser into one of the 9 portholes, and the stimulated emission is coaxially collected from the same port. Measurements from the source ( Figures 3,5,[8][9][10] were taken with the source and expansion chamber rotated by 90 and the laser injected and emission collected from what is shown as the top port in Figure 2.…”

Section: B Talifmentioning

confidence: 99%

Neutral depletion and the helicon density limit

et al. 2013

View full text Add to dashboard Cite

It is straightforward to create fully ionized plasmas with modest rf power in a helicon. It is difficult, however, to create plasmas with density >10 20 m À3 , because neutral depletion leads to a lack of fuel. In order to address this density limit, we present fast (1 MHz), time-resolved measurements of the neutral density at and downstream from the rf antenna in krypton helicon plasmas. At the start of the discharge, the neutral density underneath the antenna is reduced to 1% of its initial value in 15 ls. The ionization rate inferred from these data implies that the electron temperature near the antenna is much higher than the electron temperature measured downstream. Neutral density measurements made downstream from the antenna show much slower depletion, requiring 14 ms to decrease by a factor of 1/e. Furthermore, the downstream depletion appears to be due to neutral pumping rather than ionization. V C 2013 AIP Publishing LLC. [http://dx.

show abstract

“…3,4 Unfortunately, most prior laboratory experiments have shown the plasmas produced by these sources to be thermal. 5 Therefore, additional heating of the plasma ions is required to see efficiencies gains similar to Hall thrusters which adds to the overall power requirements to operate such a system.…”

Section: Introductionmentioning

confidence: 99%

Efficient Plasma Production in Low Background Neutral Pressures with the M2P2 Prototype

Ziemba

Euripides

Winglee

et al. 2003

39th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit

View full text Add to dashboard Cite

American Institute of Aeronautics and Astronautics 1 Mini-Magnetospheric Plasma Propulsion (M2P2) seeks the creation of a large-scale (10 km radius) magnetic wall or bubble (i.e. a magnetosphere) by the electromagnetic inflation of a small-scale (20 cm radius) dipole magnet. The inflated magnetosphere will intercept the solar wind and thereby provide high-speed propulsion with modest power and fuel requirements due to the gain provided by the ambient medium. Magnetic field inflation is produced by the injection of plasma onto the dipole magnetic field eliminating the need for large mechanical structures and added material weight at launch. For successful inflation of the magnetic bubble a beta near unity must be achieved along the imposed dipole field. This is dependent on the plasma parameters that can be achieved with a plasma source that provide continuous operation at the desired power levels of 1 to 2 kilowatts. Over the last two years we have been developing a laboratory prototype to demonstrate the inflation of the magnetic field under space-like conditions. In this paper we will present some of the latest results from the prototype development at the University of Washington and show that the prototype can produce high ionization efficiencies while operating in near space like neutral background pressures producing electron temperatures of a few tens of electron volts. This allows for operation with propellant expenditures lower then originally estimated.

show abstract

Density limit in helicon discharges

Cited by 44 publications

References 17 publications

Alfvén wave dispersion behavior in single- and multicomponent plasmas

Alfvén wave dispersion behavior in single- and multicomponent plasmas

Neutral depletion and the helicon density limit

Efficient Plasma Production in Low Background Neutral Pressures with the M2P2 Prototype

Contact Info

Product

Resources

About