Microwave measurement of decaying plasma in liquid helium

Minami, Kazuo; Kojima, C.; Ohira, Toru; Ishihara, Osamu

doi:10.1109/tps.2005.852405

Cited by 5 publications

(7 citation statements)

References 17 publications

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“…The microparticles in size of submicrometers to submillimeters have been called as dust grains or dust particles in the study of interstellar space as early as 1940s. Complex plasma has attracted much attention to the community of plasma physics [1][2][3][4], while recent advances in ultracold plasma [5][6][7][8][9] and cryogenic dusty plasma [10][11][12][13][14][15][16][17] challenge the basic understanding of plasmas. The Debye length, characterized by temperatures of electrons and ions, in a cryogenic plasma becomes much smaller than that in a conventional laboratory plasma and becomes comparable to the size of a dust particle.…”

Section: Introductionmentioning

confidence: 99%

“…A hot-filament discharge plasma was created in a vacuum chamber with an inner wall cooled by liquid nitrogen [20]. We produced cryogenic plasma by applying high voltage between needles in a gas cooled by liquid helium [7,9] where the plasma disappeared in a few seconds in a gas with 4 K electron temperature, or by applying high voltage between needles in liquid helium [8], where plasma disappeared in microseconds. Recently, we have succeeded to produce a steady plasma by an rf discharge in a vapor of liquid helium.…”

Section: Introductionmentioning

confidence: 99%

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Low-dimensional structures in a complex cryogenic plasma

Ishihara¹

2012

Plasma Phys. Control. Fusion

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Complex cryogenic plasma is theoretically and experimentally studied. In a cryogenic plasma the Debye length becomes smaller and the shielding length becomes comparable to a dust size. Dust charging in a cryogenic plasma is examined in detail by considering the polarization effect on a dust particle due to charged plasma particles. Electrons are found to be attracted to a dust particle when they come closer to a dust particle within a distance from the surface of a dust particle given by r = a((εwhere a is the radius of a spherical dust particle, ε is the dielectric constant of the dust particle, Z d is the charge state of a dust particle and λ D is the Debye length. Microscopic electron collection flux balancing with desorption electron flux determines the dust charge. Negatively charged dust particles form two-dimensional crystal structures and the displacement from the equilibrium positions shows normal modes with a dispersion relation. Experimental study determines dust charges on a cryogenic temperature.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Low-dimensional structures in a complex cryogenic plasma

Ishihara¹

2012

Plasma Phys. Control. Fusion

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“…In the monatomic gases, electron energy is lost in collisions by recoil of the atom but this mechanism is weak because of the large disparity in masses. Cooling in He has been observed for pressures of order 1 Torr, [11][12][13] but this mechanism is ineffective for pressures of order 1 mTorr.…”

Section: Apparatusmentioning

confidence: 99%

“…For example, microwave methods have been used to create and probe plasmas in cryogenic helium at 4.2 K. Goldan and Goldstein 11 measured momentum-transfer collision frequencies, electron cooling times, and electron radiation temperatures as low as 200 K. Minami et al 12,13 deduced electron temperatures from diffusion rates and found electron temperatures approaching 4 K in the afterglow of a pulsed discharge. Low electron temperatures ͑ϳ1 K͒ have also been created transiently by laser photoionization of laser-cooled 14 or expansion-cooled 15 gas near threshold.…”

Section: Introductionmentioning

confidence: 99%

Continuous gas discharge plasma with 200 K electron temperature

Dickson¹,

Robertson²

2010

Physics of Plasmas

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A very cold and collisional hot-filament discharge plasma is created in a vacuum chamber with an inner wall cooled by liquid nitrogen. The inner chamber ͑16.5 cm diameterϫ 30 cm͒ has two negatively biased tungsten filaments for plasma generation and a Langmuir probe on axis for diagnostic measurements. With the wall at 140 K, 0.5-16 mA filament emission, and 1.6 mTorr carbon monoxide as the working gas, probe data give electron temperatures of 17-28 meV ͑197-325 K͒ with corresponding densities of 10 8 -10 9 cm −3 . With He, Ar, H 2 , and N 2 at 140 K, the electron temperatures are Ͼ500 K. The lower electron temperature with CO is attributed to the asymmetric CO molecule having a larger cross section for electron excitation of rotational modes as a consequence of its dipole moment.

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“…Experimental setup YD-1 is a glass tube contained in a silver-coated glass Dewar bottle (glass cryostat) with the inner diameter of 9.6 cm and the height of 80 cm [9,36,37] . Experimental setup YD-1 is a glass tube contained in a silver-coated glass Dewar bottle (glass cryostat) with the inner diameter of 9.6 cm and the height of 80 cm [9,36,37] .…”

Section: Plasma In Cryogenic Helium Gasmentioning

confidence: 99%