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Articles 1 - 7 of 7
Full-Text Articles in Plasma and Beam Physics
Silicon Carbide Thin Film Deposition By Reactive Ion-Beam Sputtering, Larry G. Sills
Silicon Carbide Thin Film Deposition By Reactive Ion-Beam Sputtering, Larry G. Sills
Theses and Dissertations
In this study, hydrogenated amorphous silicon carbide thin films were deposited by reactive ion-beam sputtering under varying conditions to determine whether a film's optical properties can be controlled, focusing on refractive index. Using a Kaufman type ion source to sputter a pure silicon target, three distinct series of films were grown. The first series varied the mixture of methane and argon used in the ion-beam. holding all other parameters constant. For the second series the gas mix was fixed, and only the beam energy (beam voltage) was varied. The final series also varied beam energy, but was grown with a …
Plasma Transport In A Magnetic Multicusp Negative Hydrogen Ion Source, Ricky G. Jones
Plasma Transport In A Magnetic Multicusp Negative Hydrogen Ion Source, Ricky G. Jones
Theses and Dissertations
An analysis of plasma transport through the magnetic filter in tandem magnetic multicusp negative hydrogen ion sources was conducted to determine the mechanism of thermal electron diffusion, explain thermal electron cooling, describe the transport of primary electrons through the filter, and model positive ion species transport. The thermal electron flux was shown to exceed its classical value by one to three orders of magnitude. The flux variation with temperature was best described using a Coulomb-like temperature gradient drag term, consistent with diffusion due to ion-sound-like turbulence. Thermal electron energy flux loss was shown to be dominated by inelastic collisions at …
Collisional Dynamics Of The B3Π(O+) State Of Bromine Of Monofluoride, David W. Melton
Collisional Dynamics Of The B3Π(O+) State Of Bromine Of Monofluoride, David W. Melton
Theses and Dissertations
When Bromine is combined with flourine atoms and discharged oxygen in a flow tube is produced in a highly non thermal distribution peaking at v'=3. The emission was linearly dependent on the concentration. The observed dependence of the BrF(B) emission on Bromine and atomic oxygen is inconsistent with a steady state prediction of a sequential excitation mechanism, where BrF(X) is excited by successive collisions with singlet oxygen. The experimental data are consistent with a three body mechanism involving Br and F atoms. Electronic quenching of BrF(B) by a number of collision partners (Br2, CO2, O2 …
Parametric Instability Of Supersonic Shear Layers Induced By Periodic Mach Waves, Fang Q. Hu, Christopher K. W. Tam
Parametric Instability Of Supersonic Shear Layers Induced By Periodic Mach Waves, Fang Q. Hu, Christopher K. W. Tam
Mathematics & Statistics Faculty Publications
It is suggested that parametric instability can be induced in a confined supersonic shear layer by the use of a periodic Mach wave system generated by a wavy wall. The existence of such an instability solution is demonstrated computationally by solving the Floquet system of equations. The solution is constructed by means of a Fourier-Chebyshev expansion. Numerical convergence is assured by using a very large number of Fourier and Chebyshev basis functions. The computed growth rate of the induced flow instability is found to vary linearly with the amplitude of the mach waves when the amplitude is not excessively large. …
Double Tuned Cosine Coil For Nmr Imaging/Microscopy, Roger M. Hawk, Rao P. Gullapalli, Dikoma P. Shungu
Double Tuned Cosine Coil For Nmr Imaging/Microscopy, Roger M. Hawk, Rao P. Gullapalli, Dikoma P. Shungu
Journal of the Arkansas Academy of Science
The fabrication of a cosine coil having unevenly distributed struts is detailed. Placing the struts in such a manner enables a standing wave at the desired frequency and, hence, only one resonance frequency is obtained. This study details the fabrication of a cosine coil tuned to the LJ-7 frequency (77.76 MHz) and then double-tuned to the H-1 frequency (200.1 MHz) when operated at 4.7 Tesla. Double-tuning is attained by placing an LC trap in series with a capacitor used to single-tune the coil. Also, a method is suggested by which a cosine coil can be broadbanded in the lower frequency …
Electric Field Induced Emission As A Diagnostic Tool For Measurement Of Local Electric Field Strengths, A. N. Dharamsi, K. H. Schoenbach
Electric Field Induced Emission As A Diagnostic Tool For Measurement Of Local Electric Field Strengths, A. N. Dharamsi, K. H. Schoenbach
Bioelectrics Publications
The phenomenon of electric field induced (EFI) emission is examined in several diatomic and polyatomic molecules. The possibility of using this phenomenon as a diagnostic tool to measure, nonintrusively, the strength and direction of local electric fields in plasmas is discussed. An estimate of the EFI signal emitted in a typical application plasma is given. This yields a lower bound on the detector sensitivity necessary to exploit EFI emission in practical applications. It is concluded that, at present, the EFI signal could be measured by some very sensitive infrared detection schemes available. Current progress in infrared detector technology, if maintained, …
Lightning: A Complex Natural Phenomenon That Defies Simple Analysis, Mostafa Hemmati
Lightning: A Complex Natural Phenomenon That Defies Simple Analysis, Mostafa Hemmati
Journal of the Arkansas Academy of Science
No abstract provided.