Effect of negative ions on probe measurements in a chemically reacting plasma at negative probe potentials

1988 ◽  
Vol 23 (5) ◽  
pp. 778-783 ◽  
Author(s):  
G. S. Aravin ◽  
P. A. Vlasov ◽  
Yu. K. Karasevich ◽  
E. V. Makolkin ◽  
I. L. Pankrat'eva ◽  
...  
Keyword(s):  
Negative Ions ◽  
Negative Probe ◽  
Chemically Reacting ◽  
Probe Measurements

In-situdiagnostics of hydrocarbon dusty plasmas using quantum cascade laser absorption spectroscopy and mass spectrometry

2014 ◽  
Vol 80 (6) ◽  
pp. 833-841 ◽  
Author(s):  
K. Ouaras ◽  
L. Colina Delacqua ◽  
G. Lombardi ◽  
J. Röpcke ◽  
M. Wartel ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Quantum Cascade Laser ◽  
Negative Ions ◽  
Dusty Plasmas ◽  
Qualitative Comparison ◽  
Quantum Cascade ◽  
Laser Absorption ◽  
Electrostatic Probe ◽  
Probe Measurements ◽  
Reaction Characteristic

The formation of carbon nanoparticles in low pressure magnetized H2/CH4and H2/C2H2plasmas is investigated using infrared quantum cascade laser absorption, mass spectrometry, and electrostatic probe measurements. Results showed that dust formation is correlated to the presence of a significant amount of large positively charged hydrocarbon ions. Large negative ions or neutral hydrocarbon were not observed. These results, along with a qualitative comparison of diffusion and reaction characteristic, suggest that a positive ion may contribute to the growth of nanoparticles in hydrocarbon magnetized plasmas.

The operation of Langmuir probes in electro-negative plasmas

1959 ◽  
Vol 252 (1268) ◽  
pp. 102-119 ◽  
Keyword(s):  
Negative Ions ◽  
Ion Current ◽  
Langmuir Probes ◽  
Negative Probe ◽  
Ion Energy ◽  
Ion Energy Distribution ◽  
Sheath Region ◽  
Sheath Edge ◽  
Positive Ions ◽  
Positive Ion

A criterion that must be satisfied by the positive-ion energy distribution at the edge of a sheath surrounding a negative probe is derived for the case when negative ions are present. This criterion is then used to derive the potential outside the sheath region surrounding a spherical probe immersed in an electro-negative plasma. It is found that the potential falls to low values when the ratio of negative ions to electrons exceeds 2. Under these circumstances the positive-ion current collected is the random current across the sheath edge. If, however, the ratio is much less than 2 then the collection of positive ions proceeds as for an electro-positive gas.

Identification of earthquakes with the use of Sich-2 probe measurements of ionospheric plasma perturbations

2013 ◽  
Vol 19 (5(84)) ◽  
pp. 16-26
Author(s):  
V.A. Shuvalov ◽  
◽  
D.N. Lazuchenkov ◽  
S.V. Nosikov ◽  
G.S. Kochubey ◽  
...  
Keyword(s):  
Ionospheric Plasma ◽  
Probe Measurements

Pump-Probe Measurements Using Silicon Nanocrystal Waveguides

2003 ◽  
Vol 770 ◽  
Author(s):  
Nathanael Smith ◽  
Max J. Lederer ◽  
Marek Samoc ◽  
Barry Luther-Davies ◽  
Robert G. Elliman
Keyword(s):  
Probe Beam ◽  
Time Resolution ◽  
Pump Beam ◽  
Silicon Nanocrystals ◽  
Continuous Wave ◽  
Optical Gain ◽  
Optical Pump ◽  
Time Resolved ◽  
Pump Probe ◽  
Probe Measurements

AbstractOptical pump-probe measurements were performed on planar slab waveguides containing silicon nanocrystals in an attempt to measure optical gain from photo-excited silicon nanocrystals. Two experiments were performed, one with a continuous-wave probe beam and a pulsed pump beam, giving a time resolution of approximately 25 ns, and the other with a pulsed pump and probe beam, giving a time resolution of approximately 10 ps. In both cases the intensity of the probe beam was found to be attenuated by the pump beam, with the attenuation increasing monotonically with increasing pump power. Time-resolved measurements using the first experimental arrangement showed that the probe signal recovered its initial intensity on a time scale of 45-70 μs, a value comparable to the exciton lifetime in Si nanocrystals. These data are shown to be consistent with an induced absorption process such as confined carrier absorption. No evidence for optical gain was observed.

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