Experimental Studies of the Bohm Criterion in a Two-Ion-Species Plasma Using Laser-Induced Fluorescence

Severn, Greg; Wang, Xu; Ko, Eunsuk; Hershkowitz, N.

doi:10.1103/physrevlett.90.145001

Cited by 130 publications

(126 citation statements)

References 18 publications

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“…Laser induced fluorescence ͑LIF͒ measurements were made of the argon ion velocity distribution function in argon plasma using a diode laser. 37 The data given in Fig. 20͑a͒ demonstrate that the Ar + ions reach their Bohm velocity at the sheath edge as expected.…”

Section: B Laboratory Experimentssupporting

confidence: 77%

Sheaths: More complicated than you think

Hershkowitz¹

2005

Physics of Plasmas

184

162

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Sheaths in low temperature collisionless and weakly collisional plasmas are often viewed as simple examples of nonlinear physics. How well do we understand them? Closer examination indicates that they are far from simple. Moreover, many predicted sheath properties have not been experimentally verified and even the appropriate "Bohm velocity" for often encountered two-ion species plasma is unknown. In addition, a variety of sheathlike structures, e.g., double layers, can exist, and many two-and three-dimensional sheath effects have not been considered. Experimental studies of sheaths and presheaths in weakly collisional plasmas are described. A key diagnostic is emissive probes operated in the "limit of zero emission." Emissive probes provide a sensitive diagnostic of plasma potential with a resolution approaching 0.1 V and a spatial resolution of 0.1 cm. Combined with planar Langmuir probes and laser-induced fluorescence, they have been used to investigate a wide variety of sheath, presheath, and sheathlike structures. Our experiments have provided some answers but have also raised more questions.

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Section: B Laboratory Experimentssupporting

confidence: 77%

Sheaths: More complicated than you think

Hershkowitz¹

2005

Physics of Plasmas

184

162

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“…This result was confirmed by the recent study of the sheath in two-component plasma, performed by Severn et al 14 Based on the similarity of experimental conditions, we assume here as well that all species in multicomponent FPS plasma have the same Bohm velocity in the form of Eq. (5).…”

Section: Introductionsupporting

confidence: 84%

Measuring the plasma density of a ferroelectric plasma source in an expanding plasma

Dunaevsky

Fisch

2004

Journal of Applied Physics

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The initial density and electron temperature at the surface of a ferroelectric plasma source were deduced from floating probe measurements in an expanding plasma. The method exploits negative charging of the floating probe capacitance by fast flows before the expanding plasma reaches the probe. The temporal profiles of the plasma density can be obtained from the voltage traces of the discharge of the charged probe capacitance by the ion current from the expanding plasma. The temporal profiles of the plasma density, at two different distances from the surface of the ferroelectric plasma source, could be further fitted by using the density profiles for the expanding plasma. This gives the initial values of the plasma density and electron temperature at the surface. The method could be useful for any pulsed discharge, which is accompanied by considerable electromagnetic noise, if the initial plasma parameters might be deduced from measurements in expanding plasma.

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“…Many works have investigated the collisional and magnetized plasma sheath containing ion and electron. Besides the works studying two-component plasma sheath composed of ion and electron, the investigation of multi-component plasma sheath has recently drawn considerable attention [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39]. For example, experimental investigation of plasma sheath containing two positive ions can be found in Refs.…”

Section: Introductionmentioning

confidence: 99%

“…For example, experimental investigation of plasma sheath containing two positive ions can be found in Refs. [34][35][36][37]. References [34] and [35] have investigated the plasma sheath containing two positive ions, Ar , experimentally, using dc hot-filament multidipole plasma system.…”

Section: Introductionmentioning

confidence: 99%

Magnetized plasma sheath with two positive ions where collision frequencies have a power law dependency on ions velocities

Masoudi

Khoramabadi

2015

J Theor Appl Phys

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We study the dynamics of collisional magnetized plasma sheath with two species of positive ions by using the plasma fluid model. The basic equations of the fluid model are solved numerically where the sheath is in the external magnetic field and the elastic collision between ions and neutrals has been taken into account. In our model, we assume that the collisional momentum transferring cross section has a power law dependency on ion flow velocity. Our analysis demonstrates that the sheath dynamics are sensitive to the power law dependency, especially for the ion with greater density.

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Experimental Studies of the Bohm Criterion in a Two-Ion-Species Plasma Using Laser-Induced Fluorescence

Cited by 130 publications

References 18 publications

Sheaths: More complicated than you think

Sheaths: More complicated than you think

Measuring the plasma density of a ferroelectric plasma source in an expanding plasma

Magnetized plasma sheath with two positive ions where collision frequencies have a power law dependency on ions velocities

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