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Observations of rapidly formed (<50–300 ns) distributed plasma discharges using X-band microwaves in neon and Ne(Ar) mixture gases are presented. A stainless steel cylindrical discharge test chamber, which is enclosed with polycarbonate windows on both ends, is used to observe microwave breakdown in noble gases including Penning discharge Ne(Ar) and Ne(Kr) mixes from 10 to 760 torr. The chamber...
Observations of rapidly formed (<50–300 ns) distributed plasma discharges using X-band microwaves in neon with 1 mTorr residual air are presented. A stainless steel cylindrical discharge test chamber, which is enclosed with polycarbonate windows on both ends, is used to observe microwave breakdown in neon gas from 10 to 760 torr. The chamber is illuminated by the output of 25 kW, 0.8 µs pulse-width,...
Observations of rapidly formed (<50−400 ns) distributed plasma discharges using X-band microwaves in Neon with 1 mTorr residual air are presented. A stainless steel cylindrical discharge test chamber is used to observe microwave breakdown at 10 to 760 torr pressures. The chamber is enclosed with polycarbonate windows on both ends and has two side ports. The magnetron illuminates the chamber using...
Preliminary observations of rapidly formed (<50 ns) distributed plasma discharges using X-band microwaves are presented. The following setup establishes the conditions necessary to study complex microwave discharges. The microwave discharge test chamber is an L-band brass rectangular waveguide with polycarbonate windows. The chamber is illuminated by the output of 25 kW, 0.8 µs pulse-width,...
Summary form only given. Measurements and analysis of air breakdown processes and plasma production by focusing 193 nm, 260 mJ, 10 MW high power laser radiation inside a 6 cm diameter helical RF coil. We observe quantum resonant multi-photon (REMPI)[1] and collisional cascade laser ionization processes that produce high density (ne~7 × 1016/cc) cylindrical seed plasmas at 760 Torr. The focused laser...
Summary form only given. Field emission from cold copper knife-edge cathodes was experimentally studied by measuring emission currents on the Madison cathode experiment (MACX) in UHV with a base pressure of 10-10 Torr. The cathode was machined first using EDM to produce raised ridges or knife-edges of 0.13 mm width and 0.75 mm depth. The knife-edge width was further reduced by chemically etching it...
Summary form only given. Measurements and analysis of air breakdown processes by focusing a 193 nm, 200 mJ, 10 MW high power UV laser radiation to 20-60 ??m spot sizes that produce maximum laser intensities of 1012-1013 W/cm2 are presented. Both classical quantum (multi-photon) and (collisional cascade) ionization processes affect the breakdown and plasma formation. Observations are made for a wide...
We report the experimental study of field emission from cold cathodes having a raised ridge or knife-edge structure and analyses using a Transfer Matrix Method (TMM) model used to extract the cathode parameters. Local emission current measurements were done on a copper cathode, which was fabricated using electric discharge machining (EDM) and chemical etching yielding ridges of thickness 15 mum. Measurements...
We report the measurements and analysis of air breakdown process by focusing 193 nm, 200 mJ, 10 MW high power UV laser radiation onto a 20-60 mum spot size that produces a maximum laser intensity of 1012-1013 W/cm2, well above the threshold flux for air ionization. The breakdown threshold is measured and compared with theoretical models including classical (collisional cascade) and quantum (multi-photon)...
Summary form only given. We report the measurements and analysis of metal cold field emission cathodes utilizing an advanced cathode test facility and a TMM (transfer matrix method) model. The facility is designed to measure the field emission currents from cathodes on the micro- and macroscale. Measurements are obtained under UHV (10-10 torr) conditions. The vacuum chamber is a stainless steel six-way...
This paper reports on measurements and analyses of field emission from both copper and aluminium cathodes. To analyze the data, a numerical model of electron emission was developed using a transfer matrix function method. The work function and effective field enhancement factor of the cathodes were obtained.
We report measurements and analyses of field emission from both copper and aluminum cathodes. To analyze the data, we have developed a numerical model of electron emission. We note that localized heating of high current density field emission cathodes can provide regime where thermionic as well as field emission effects must be considered. Our analysis of experimental data fitting in both the thermionic...
Summary form only given. The measurements and analysis of air breakdown processes by focusing 193 nm, 200 mJ, 10 MW high power UV laser radiation on to a 10-20 mum spot size that produces laser power densities up to 1012-1013 W/cm2, well above the threshold power flux for air ionization will be presented. The breakdown threshold is measured and compared with classical and quantum theoretical models...
Summary form only given. We report the measurements and analysis of air breakdown process by focusing 193 nm, 200 mJ, 10 MW high power UV laser radiation on to a 10-20 mum spot size that can produce a maximum laser intensity of 1012-1013 W/cm2, and well above the threshold flux for air ionization. The breakdown threshold is measured and compared with the theoretical models such as classical and quantum...
We report measurements and analysis of metal cold field emission cathodes utilizing an advanced cathode test facility. The facility is designed to measure the field emission current densities from cathodes on the Micro-and Macro-scale. Measurements are obtained under UHV vacuum (10~10 Torr) conditions. The vacuum chamber is a stainless steel six-way cross. We use a scroll pump, turbo pump and a Vacion...
Summary form only given. A fast-pulsed, UV laser-initiated, RF-sustained high pressure plasma source has been developed and optimized for more efficient large volume (ges1000 cc), high pressure plasma generation. We have shown that during the tast-pulsed plasma formation, the plasma load impedance as seen by the helical antenna varies significantly from 0.5+j125 Omega to 4.0+j130 Omega on short time...
We report the measurements and analysis of air breakdown processes by focusing 193 nm, 200 mJ, 10 MW high power UV laser radiation on to a 10 - 20 mum spot size that produces laser power densities up to 1012 -1013 W/cm2 , well above the threshold power flux for air ionization. The breakdown threshold is measured and compared with classical and quantum theoretical models. A universal scaling analysis...
We report measurements and analysis of metal cold field emission cathodes utilizing an advanced cathode test facility. The facility is designed to measure the field emission current densities from cathodes on the Micro- and Macro-scale.
We report the design, construction and initial operation of an advanced, high-current-density, field emission cathode facility. The facility is designed to examine the nanophysics of field emission from advanced Al, Ni, C, CsI, Mo, and other material cathodes that operate in the 1-1000 A/cm2 regime. Operation is designed for UHV vacuum (10-10 Torr) with bake-out provisions up to temperatures of 450...
Summary form only given. Experiments are performed using 193 nm ultraviolet (UV) laser pre-ionization of a seed gas in atmospheric pressure range argon or nitrogen to initiate a discharge that is sustained by 13.56 MHz radiofrequency (RF) power using efficient inductive wave coupling. High-density (1012-1013/cm3), large-volume (~500 cm 3) 760 torr argon plasma is initiated and maintained for 300 ms...
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