Co-axial multicusp source for low axial energy spread ion beam production

Lee, Y; Gough, Richard; Leung, K. N.; Vujic, J.; Williams, M. D.; Zahir, N.

doi:10.1016/s0168-9002(99)00274-0

Cited by 3 publications

(2 citation statements)

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“…Transverse magnetic filters such as the one employed in this source have been shown to be effective in modifying substantially the energy distribution of electrons in the extracted plasma. 4 Energetic electrons within the discharge chamber are prevented from crossing the magnetic field lines of the filter and following the ions exiting the discharge chamber (which themselves are largely unimpeded by the magnetic field). Low-energy electrons, however, are able to diffuse through the filter, and follow the ions, through momentum-exchange collisions with other electrons and with the other species within the source.…”

Section: A Magnetically-filtered Plasma Sourcementioning

confidence: 99%

Characterization of a Plasma Source for Ground-Based Simulation of LEO Plasma Conditions

Enloe¹,

Krause²,

McHarg³

et al. 2004

2nd International Energy Conversion Engineering Conference

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We characterize the parameters of the flowing argon plasma produced by a 16-cmdiameter plasma source utilizing a transverse magnetic filter to reduce electron temperature while maintaining the quasineutrality of the flowing plasma, as a function of the operating parameters of the source: discharge voltage, discharge current, and gas flow rate/neutral background pressure. We evaluate the plasma parameters against the desirable characteristics of a low-Earth-orbit (LEO) plasma simulator, namely, cold particle distributions with a Mach number (relative to the ion acoustic speed of the plasma) characteristic of LEO spacecraft. We measure electron temperatures from 0.5 to 0.8 eV and ion temperatures from 0.7 to 1.3 eV, with greater than 95% of the ions and 70 to 80% of the electrons in the thermal distribution. The flow is characterized by Mach numbers from 2.7 to 3.9, with Debye lengths in the plasma as low as 0.4 cm. Using a suite of two instruments, a traditional planar retarding potential analyzer (RPA) and a unique miniature electrostatic analyzer (MESA) "laminated analyzer" developed as a rugged, mass-producible survey instrument for spacecraft, we are able to validate the measurements of the former instrument and demonstrate the utility of the latter device in a realistic plasma environment. Based on the behavior of the source with the measurements we have made to date (such as the direct proportionality of downstream plasma density to the discharge current in the source) we see a clear path forward to further improvements in the source as a viable LEO plasma simulator.

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Section: A Magnetically-filtered Plasma Sourcementioning

confidence: 99%

Characterization of a Plasma Source for Ground-Based Simulation of LEO Plasma Conditions

Enloe¹,

Krause²,

McHarg³

et al. 2004

2nd International Energy Conversion Engineering Conference

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“…Magnetic filter-equipped plasma sources that use multicusp magnetic field configurations may have applications as 3 Author to whom any correspondence should be addressed. ion sources in focused ion beam (FIB) lithography systems because they are capable of producing very low-energy-spread ion beams with correspondingly high emittance [8]. These plasma sources exhibit very low electron temperatures on the order of 0.1 eV in the region downstream of the magnetic filter and careful design of the filter layout and discharge chamber magnetic fields enables ion beams to be produced from plasma with ion energy spreads that are as low as 0.6 eV [8].…”

Section: Introductionmentioning

confidence: 99%

Magnetic filter type plasma source for ground-based simulation of low earth orbit environment

Rubin¹,

Farnell²,

Williams³

et al. 2009

Plasma Sources Sci. Technol.

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Simulation of the low Earth orbit (LEO) plasma environment in ground-based vacuum facilities is important for studies of spacecraft interaction with ionospheric plasmas. In this paper we describe the design and performance of a magnetic filter-equipped plasma source. Experimental data collected in the expanding plasma downstream of the source suggest it is a good candidate for use as a LEO plasma simulator in that the expanding plasma has a very low electron temperature and contains streaming ions-the plasma environment encountered by satellites in LEO. Adjustable plasma source operating conditions of flow rate, discharge current and discharge voltage enable production of plasma electron temperatures over the range from 0.17 to 0.35 eV and streaming ion energies over the range from 1 to 4 eV.

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