Plasma diagnostics of the Grimm-type glow discharge

Kuraica, M. M.; Konjević, N.; Platiša, M.; Pantelić, Dejan

doi:10.1016/0584-8547(92)80110-3

Cited by 82 publications

(65 citation statements)

References 23 publications

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“…<1 Torr) pure hydrogen, and RF and DC generated H 2 /Ar plasmas [1][2][3][4][5][6][7][8][9][10]. New reports continue to appear [11], and now there are several reports from our team that selective H α line broadening is found in other plasmas called resonant-transfer (rt)-plasmas including H 2 /He (RF-GEC-type cell, [12]), water (microwave [13] and RF-GEC-type cell [14]) and in the presence of certain catalysts including helium, argon, potassium, and strontium (glow discharge, RF-GEC, and filament-type cells [15][16][17][18][19][20][21][22]).…”

Section: Introductionmentioning

confidence: 99%

Evidence of catalytic production of hot hydrogen in RF generated hydrogen/argon plasmas

Phillips

Chen

Akhtar

et al. 2007

International Journal of Hydrogen Energy

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This is the third in a series of papers by our team on apparently anomalous Balmer series line broadening in hydrogen containing RF generated, low pressure (< 600 mTorr) plasmas. In this paper the selective broadening of the atomic hydrogen lines in pure H 2 and Ar/H 2 mixtures in a large 'GEC' cell (36 cm length × 14 cm ID) was mapped as a function of position, H 2 /Ar ratio, time, power, and pressure. Several observations regarding the selective line broadening were particularly notable as they are unanticipated on the basis of earlier models. First, the anomalous broadening of the Balmer lines was found to exist throughout the plasma, and not just in the region between the electrodes. Second, the broadening was consistently a complex function of the operating parameters particularly gas composition (highest in pure H 2 ), position, power, time and pressure. Clearly not anticipated by earlier models were the findings that under some conditions the highest concentration of 'hot' (>10 eV) hydrogen was found at the entry end, and not in the high field region between the electrodes and that in other conditions, the hottest H was at the (exit) pump (also grounded electrode) end. Third, excitation and electron temperatures were less than one eV in all regions of the plasma not directly adjacent (>1mm) to the electrodes, a Corresponding author: phone 505-665-2682; fax 505-665-5548 jphillips@LanL.gov 2 providing additional evidence that the energy for broadening, contrary to standard models, is not obtained from the field. Fourth, in contrast to our earlier studies of hydrogen/helium and water plasmas, we found that in some conditions 98% of the atomic hydrogen was in the 'hot' state throughout the GEC-type cell. Virtually every operating parameter studied impacted the character of the hot H atom population, and clearly second and third order effects exist, indicating a need for experimental design. Some non-field mechanisms for generating hot hydrogen atoms, specifically those suggested by Mills' CQM model, are outlined.3

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Section: Introductionmentioning

confidence: 99%

Evidence of catalytic production of hot hydrogen in RF generated hydrogen/argon plasmas

Phillips

Chen

Akhtar

et al. 2007

International Journal of Hydrogen Energy

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“…Many groups report (anomalous) line broadening of atomic hydrogen lines in mixed gas plasmas containing argon in high field regions [6][7][8][9][10][11][12][13][14][15][16][17]. A similar phenomenon has been observed in pure hydrogen plasmas, generated with DC discharge or RF systems including one group using a GEC cell [4,7,17].…”

Section: Discussionmentioning

confidence: 87%

“…Recently, [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] unique and dramatic H α line broadening has been observed in a variety of laboratories in specific mixed gas plasmas, particularly Ar/H 2 plasmas, operated at low pressure (milli-Torr) and generated, with microwave and glow discharge systems. It is universally agreed that the broadening must be Doppler broadening.…”

Section: Introductionmentioning

confidence: 99%

“…One class of mechanisms can be called field acceleration (FA) models because, in all the various permutations of this class of models, it is necessary for the energy to be given to the hydrogen from the field. For example, it is postulated that ionic molecular hydrogen is accelerated in the cathode fall region, then is neutralized and picks up charge from Ar ions, and finally dissociates and emits [6][7][8][9][10][11][12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

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Evidence of catalytic production of hot atomic hydrogen in RF generated hydrogen/helium plasmas

Phillips¹,

Chen²

2008

International Journal of Hydrogen Energy

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A study of the line shapes of hydrogen Balmer series lines in RF generated low pressure H 2 /He plasmas produced results suggesting a catalytic process between helium and hydrogen species results in the generation of 'hot' (ca. 28 eV) atomic hydrogen.Even far from the electrodes 'hot' atomic hydrogen was predominant in H 2 /He plasmas.Line shapes, relative line areas of cold and hot atomic hydrogen (hot/cold>2.5), were very similar for areas between the electrodes and far from the electrodes for these plasmas. In contrast, in H 2 /Xe only 'warm' (<5 eV) hydrogen (warm/cold<1.0) was found between the electrodes, and only cold hydrogen away from the electrodes. Earlier postulates that preferential hydrogen line broadening in plasmas results from the acceleration of ionic hydrogen in the vicinity of electrodes, and the special charge exchange characteristics of Ar/H 2 + are clearly belied by the present results that show atomic hydrogen line shape are similar for H 2 /He plasmas throughout the relatively large cylindrical (14 cm ID x 36 cm length) cavity.

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“…al. [10] and described in detail elsewhere [2]. Here, for completeness, minimum details will be given.…”

Section: Methodsmentioning

confidence: 99%

Influence of cathode temperature on abnormal glow discharge properties

2006

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In this paper the influence of cathode temperature on abnormal glow discharge properties is examined. A Grimm type glow discharge with no cathode cooling, operating in argon and argon hydrogen mixture is used. Dependence of spectral line intensities of argon, hydrogen and lines of cathode material upon cathode temperature is measured. Change of discharge voltage with measured cathode temperature is also reported. These changes may be attributed to the rise of gas temperature due to the heat transfer form the cathode.

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Plasma diagnostics of the Grimm-type glow discharge

Cited by 82 publications

References 23 publications

Evidence of catalytic production of hot hydrogen in RF generated hydrogen/argon plasmas

Evidence of catalytic production of hot hydrogen in RF generated hydrogen/argon plasmas

Evidence of catalytic production of hot atomic hydrogen in RF generated hydrogen/helium plasmas

Influence of cathode temperature on abnormal glow discharge properties

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