Author: K. T. Yen
Publisher:
ISBN:
Category :
Languages : en
Pages : 19
Book Description
An analytical study of the interaction between microwaves and a fully-ionized gas behind a normal shock wave is presented. The governing differential equations derived by a quasi-steady analysis are used to obtain the non-dimensional parameters and integrated to yield the first integrals of the momentum and energy equations. A modified Prandtl relation is derived from which the final equilibrium state of the ionized gas can be found. Ionization is seen to increase the final equilibrium density, while microwave heating tends to reduce its value. It is further shown that thermal choking of the ionized gas occurs at a critical microwave power level, which is a function of the Mach number ahead of the shock wave, the reflection coef ficient of the microwave, and the ionization potential expressed in terms of the neutral gas temperature ahead of the shock wave. At higher power levels the shock wave moves upstream allowing additional microwave heating of the ionized gas. A formula is given for the determi nation of this equivalent higher Mach number. At a sufficiently high power level (but slightly below the critical value), the mean gas tempera ture is shown to attain a peak value higher than its final equilibrium value. This peak temperature actually represents the upper bound of the mean gas temperature for a given initial Mach number. (Author).
Effect of Microwave Radiation on the Ionized Gas Ba Strong Normal Shock Wave
Author: K. T. Yen
Publisher:
ISBN:
Category :
Languages : en
Pages : 19
Book Description
An analytical study of the interaction between microwaves and a fully-ionized gas behind a normal shock wave is presented. The governing differential equations derived by a quasi-steady analysis are used to obtain the non-dimensional parameters and integrated to yield the first integrals of the momentum and energy equations. A modified Prandtl relation is derived from which the final equilibrium state of the ionized gas can be found. Ionization is seen to increase the final equilibrium density, while microwave heating tends to reduce its value. It is further shown that thermal choking of the ionized gas occurs at a critical microwave power level, which is a function of the Mach number ahead of the shock wave, the reflection coef ficient of the microwave, and the ionization potential expressed in terms of the neutral gas temperature ahead of the shock wave. At higher power levels the shock wave moves upstream allowing additional microwave heating of the ionized gas. A formula is given for the determi nation of this equivalent higher Mach number. At a sufficiently high power level (but slightly below the critical value), the mean gas tempera ture is shown to attain a peak value higher than its final equilibrium value. This peak temperature actually represents the upper bound of the mean gas temperature for a given initial Mach number. (Author).
Publisher:
ISBN:
Category :
Languages : en
Pages : 19
Book Description
An analytical study of the interaction between microwaves and a fully-ionized gas behind a normal shock wave is presented. The governing differential equations derived by a quasi-steady analysis are used to obtain the non-dimensional parameters and integrated to yield the first integrals of the momentum and energy equations. A modified Prandtl relation is derived from which the final equilibrium state of the ionized gas can be found. Ionization is seen to increase the final equilibrium density, while microwave heating tends to reduce its value. It is further shown that thermal choking of the ionized gas occurs at a critical microwave power level, which is a function of the Mach number ahead of the shock wave, the reflection coef ficient of the microwave, and the ionization potential expressed in terms of the neutral gas temperature ahead of the shock wave. At higher power levels the shock wave moves upstream allowing additional microwave heating of the ionized gas. A formula is given for the determi nation of this equivalent higher Mach number. At a sufficiently high power level (but slightly below the critical value), the mean gas tempera ture is shown to attain a peak value higher than its final equilibrium value. This peak temperature actually represents the upper bound of the mean gas temperature for a given initial Mach number. (Author).
Effect of Microwave Radiation on the Ionized Gas Behind a Strong Normal Shock Wave
Author: K. T. Yen
Publisher:
ISBN:
Category : Ionized gases
Languages : en
Pages : 19
Book Description
Publisher:
ISBN:
Category : Ionized gases
Languages : en
Pages : 19
Book Description
Ionized Shock Front Analysis. Part Iii. Effect of Joule Heating on Electron Density Level and Microwave Properties Downstream of a Strong Shock Wave
Author: MELVIN. EPSTEIN
Publisher:
ISBN:
Category :
Languages : en
Pages : 1
Book Description
An investigation was carried out of the interaction between a slightly ionized gas downstream of a shock wave and a microwave of sufficient strength to at least slightly alter the electron density level in the gas. The particular type of interaction is that resulting from the Joule heating of the gas. It is assumed that the gas is always in complete equilibrium and so the results may be considered to be valid only in the limiting case of collision frequency large compared to the signal frequency. The calculations indicate that this type of interaction may produce significant increases in electron density level for field strengths as low as one volt/cm under the appropriate conditions. (Author).
Publisher:
ISBN:
Category :
Languages : en
Pages : 1
Book Description
An investigation was carried out of the interaction between a slightly ionized gas downstream of a shock wave and a microwave of sufficient strength to at least slightly alter the electron density level in the gas. The particular type of interaction is that resulting from the Joule heating of the gas. It is assumed that the gas is always in complete equilibrium and so the results may be considered to be valid only in the limiting case of collision frequency large compared to the signal frequency. The calculations indicate that this type of interaction may produce significant increases in electron density level for field strengths as low as one volt/cm under the appropriate conditions. (Author).
Effect of Microwave Radiation on a Shock-Produced Electron Precursor
Author: Samuel Lederman
Publisher:
ISBN:
Category :
Languages : en
Pages : 25
Book Description
The paper presents some results of experiments in which a small pressure driven shock tube was used to produce shocks in Argon above Mach 10. This was strong enough to produce low level precursor ionization ahead of the shock. At the same time, the shock tube was used as a waveguide for pulsed X-Band microwave radiation with a peak power of a few kilowatts. This further ionized the gas in the precursor region, resulting in an ionization wave which propagated very rapidly toward the microwave source. The velocity of this wave was measured as a function of the microwave power and an interpretation and comparison with other data is given. (Author).
Publisher:
ISBN:
Category :
Languages : en
Pages : 25
Book Description
The paper presents some results of experiments in which a small pressure driven shock tube was used to produce shocks in Argon above Mach 10. This was strong enough to produce low level precursor ionization ahead of the shock. At the same time, the shock tube was used as a waveguide for pulsed X-Band microwave radiation with a peak power of a few kilowatts. This further ionized the gas in the precursor region, resulting in an ionization wave which propagated very rapidly toward the microwave source. The velocity of this wave was measured as a function of the microwave power and an interpretation and comparison with other data is given. (Author).
Applied Mechanics Reviews
Ionized Shock Front Analysis
Author: Melvin Epstein
Publisher:
ISBN:
Category : Electromagnetic theory
Languages : en
Pages : 44
Book Description
Publisher:
ISBN:
Category : Electromagnetic theory
Languages : en
Pages : 44
Book Description
Structure of a Strong Normal Shock Wave Due to Nonequilibrium Radiation and Collisional Ionization
Author: Carlo Ferrari
Publisher:
ISBN:
Category :
Languages : en
Pages : 40
Book Description
The general theory about gas-dynamics with nonequilibrium radiative and collisional ionization is applied to the strong normal shock wave. It is shown that the problem is reduced to the solution of a system of two non-linear integral equations. It is proved that, if certain conditions are satisfied, an iteration method, to resolve these equations, can be applied; it turns out then that the fundamental parameter controlling the convergence or non convergence of the procedure is the value of the degree of ionization just on the front of the shock. Numerical results are given and the physical complete structure of the shock is analyzed. (Author).
Publisher:
ISBN:
Category :
Languages : en
Pages : 40
Book Description
The general theory about gas-dynamics with nonequilibrium radiative and collisional ionization is applied to the strong normal shock wave. It is shown that the problem is reduced to the solution of a system of two non-linear integral equations. It is proved that, if certain conditions are satisfied, an iteration method, to resolve these equations, can be applied; it turns out then that the fundamental parameter controlling the convergence or non convergence of the procedure is the value of the degree of ionization just on the front of the shock. Numerical results are given and the physical complete structure of the shock is analyzed. (Author).
Normal Ionizing Shock Waves; the Effects of Equilibrium, Dissociation and Ionization
Author: Robert Taussig
Publisher:
ISBN:
Category :
Languages : en
Pages : 61
Book Description
Solutions for a model of a normal ionizing shock wave in an electromagnetic field are obtained. The model considers an ideal monatomic gas, and includes the equilibrium composition of the gas, the chemical energy of ionization and dissociation absorbed at the shock front. Solutions for this more complex, and more realistic, model are called solutions with chemistry, in contrast to the ideal gas solutions for the simple model analyzed before. The gas is composed of four chemical species, H sub 2 H, H(+), and e( - ), assumed to be at chemical equilibrium upstream and downstream from the shock.
Publisher:
ISBN:
Category :
Languages : en
Pages : 61
Book Description
Solutions for a model of a normal ionizing shock wave in an electromagnetic field are obtained. The model considers an ideal monatomic gas, and includes the equilibrium composition of the gas, the chemical energy of ionization and dissociation absorbed at the shock front. Solutions for this more complex, and more realistic, model are called solutions with chemistry, in contrast to the ideal gas solutions for the simple model analyzed before. The gas is composed of four chemical species, H sub 2 H, H(+), and e( - ), assumed to be at chemical equilibrium upstream and downstream from the shock.
Non-Ideal Gas Effects on Shock Waves in Weakly Ionized Gases
Author: Robert Rubinstein
Publisher:
ISBN:
Category :
Languages : en
Pages : 14
Book Description
A shock wave in a weakly ionized gas can be preceeded by a charge separation region if the Debye length is larger than the shock width. It has been proposed that electrostatic contributions to pressure in the charge separation region can increase the sound speed ahead of the shock well above the sound speed in a neutral gas at the same temperature and therefore increase the shock propagation speed. This proposal is investigated numerically and theoretically. It is concluded that although the ion gas becomes strongly non-ideal in the charge separation region, there is no appreciable effect on the neutral shock.
Publisher:
ISBN:
Category :
Languages : en
Pages : 14
Book Description
A shock wave in a weakly ionized gas can be preceeded by a charge separation region if the Debye length is larger than the shock width. It has been proposed that electrostatic contributions to pressure in the charge separation region can increase the sound speed ahead of the shock well above the sound speed in a neutral gas at the same temperature and therefore increase the shock propagation speed. This proposal is investigated numerically and theoretically. It is concluded that although the ion gas becomes strongly non-ideal in the charge separation region, there is no appreciable effect on the neutral shock.