Download or read book Wave Propagation in a Hot Magnetoplasma with Coulomb Collisions written by Robert J. Papa and published by . This book was released on 1970 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Wave Propagation in a Warm Magnetoplasma with Coulomb Interactions written by Robert J. Papa and published by . This book was released on 1970 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: Electromagnetic waves propagating through partially ionized gases can be severely attenuated and suffer distortion. This has important consequences in the design of any communication and radar system in which waves must propagate through an intervening plasma medium, such as in reentry communications and ionospheric propagation. In this report, formulas are derived that can predict such wave attenuation characteristics more accurately and for a wider range of plasma conditions than already existing theories. The conventional Appleton-Hartree equation used in ionospheric propagation studies gives the index of refraction of a wave travelling through a plasma in a magnetic field in terms of the properties of the plasma. This conventional Appleton-Hartree formula neglects important effects such as the random thermal motion of the particles, which can cause nonlocal effects. Also, the energy dependence of the electron-neutral collision frequency can alter the nature of the wave attenuation process. In the report, a generalization of the Appleton-Hartree equation is made to include these effects. A kinetic equation is solved which includes the effects of energy-dependent electron-neutral collisions, Coulomb encounters and spatial dispersion. The perturbation method used in solving the kinetic equation assumes that the effects of electron-neutral collisions and Coulomb encounters are dominant, and spatial dispersion effects are weak.

Download or read book Wave Propagation in a Hot Magnetoplasma with Coulomb Collisions written by Robert J. Papa and published by . This book was released on 1970 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Wave Propagation in a Hot Magnetoplasma with Velocity Dependent Collision Frequencies and Coulomb Encounters written by Robert John Papa and published by . This book was released on 1972 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Theory of Electromagnetic Wave Propagation in a Hot Magnetoplasma written by Robert J. Papa and published by . This book was released on 1969 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A brief discussion is given of the physical processes that occur in a hot magnetoplasma, and the results are compared to a cold plasma model. The conventional linearization of the Boltzmann equation is discussed, where the electron distribution function is expanded in terms of a small parameter proportional to the externally imposed electric field. Particle collisions are described by a relaxation model for the electron-neutral collision integral. The plasma is assumed to be Lorentzian, so that Coulomb collisions and ion motion are both neglected. Explicit expressions for the components of the conductivity tensor are given in Cartesian coordinates and in the principal coordinate system in which the conductivity tensor is symmetric. By asymptotically expanding the components of the conductivity tensor, it is shown how the dispersion relation determining the index of refraction becomes a relatively simple cubic equation. The Clemmow-Mullaly-Allis diagram is discussed for a warm plasma. Finally, the derivation of the radiation resistance of a short antenna in a hot, isotropic plasma is carried out in detail. (Author)

Download or read book Numerical Solution of the Dispersion Relations for a Hot Magnetoplasma with Collisions written by Robert J. Papa and published by . This book was released on 1972 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt: Detailed numerical studies have been made on the dispersion relations for electromagnetic waves propagating in partially ionized gases immersed in a dc magnetic field. Accurate values of the attenuation constant and phase shift are needed in the design of radio communications systems where waves must propagate through an ionized gas (such as in reentry communications systems), in the design of radar jamming devices used during missile reentry, and in the analytical study of ionospheric propagation phenomena. The numerical solution of the dispersion relations enable the effects of collisionless wave damping, velocity-dependent electron-neutral collisions, and Coulomb encounters to be studied. The attenuation and phase shift of waves propagating through a plasma are dependent upon the signal frequency, plasma temperature, plasma density, degree of ionization, and cross sections for electron scattering. Graphs are presented which enable attenuation constants and phase shifts to be readily evaluated for a very wide range of possible plasma conditions. (Author).

Download or read book Theory of Electromagnetic Wave Propagation in a Hot Magnetoplasma written by Robert J. Papa and published by . This book was released on 1969 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt: A brief discussion is given of the physical processes that occur in a hot magnetoplasma, and the results are compared to a cold plasma model. The conventional linearization of the Boltzmann equation is discussed, where the electron distribution function is expanded in terms of a small parameter proportional to the externally imposed electric field. Particle collisions are described by a relaxation model for the electron-neutral collision integral. The plasma is assumed to be Lorentzian, so that Coulomb collisions and ion motion are both neglected. Explicit expressions for the components of the conductivity tensor are given in Cartesian coordinates and in the principal coordinate system in which the conductivity tensor is symmetric. By asymptotically expanding the components of the conductivity tensor, it is shown how the dispersion relation determining the index of refraction becomes a relatively simple cubic equation. The Clemmow-Mullaly-Allis diagram is discussed for a warm plasma. Finally, the derivation of the radiation resistance of a short antenna in a hot, isotropic plasma is carried out in detail. (Author).

Download or read book Wave Propagation in a Warm Magnetoplasma with Coulomb Interactions written by Robert J. Papa and published by . This book was released on 1970 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Electromagnetic waves propagating through partially ionized gases can be severely attenuated and suffer distortion. This has important consequences in the design of any communication and radar system in which waves must propagate through an intervening plasma medium, such as in reentry communications and ionospheric propagation. In this report, formulas are derived that can predict such wave attenuation characteristics more accurately and for a wider range of plasma conditions than already existing theories. The conventional Appleton-Hartree equation used in ionospheric propagation studies gives the index of refraction of a wave travelling through a plasma in a magnetic field in terms of the properties of the plasma. This conventional Appleton-Hartree formula neglects important effects such as the random thermal motion of the particles, which can cause nonlocal effects. Also, the energy dependence of the electron-neutral collision frequency can alter the nature of the wave attenuation process. In the report, a generalization of the Appleton-Hartree equation is made to include these effects. A kinetic equation is solved which includes the effects of energy-dependent electron-neutral collisions, Coulomb encounters and spatial dispersion. The perturbation method used in solving the kinetic equation assumes that the effects of electron-neutral collisions and Coulomb encounters are dominant, and spatial dispersion effects are weak.

Download or read book Collisional Effects on Waves in a Magnetoplasma written by John Quayle Howell and published by . This book was released on 1970 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new class of collision-dependent electron waves is found in a non-Maxwellian Lorentz magnetoplasma, and it is shown that these waves may be driven unstable by electron-neutral collisions. The Boltzmann equation with collision integral is solved, assuming propagation either parallel or perpendicular to the magnetic field. Both conductivity tensors are derived and put in a form useful for numerical calculations. The full set of Maxwell's equations is then used to derive the dispersion relations for both directions of propagation. The dispersion relations are initially solved for a monoenergetic electron distribution function and following that a distribution with a peak of nonzero halfwidth is treated. Some consideration is also given to a Maxwellian distribution both with and without a bump on the tail. As an example of propagation parallel to the magnetic field, transverse electromagnetic or whistler waves are considered. (Author).

Download or read book Electron Wave Instabilities in a Magnetoplasma Caused by Electron neutral Collisions written by John Q. Howell and published by . This book was released on 1971 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Solution of the Dispersion Relations for a Hot Magnetoplasma with Collisions written by Robert J. Papa and published by . This book was released on 1972 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Detailed numerical studies have been made on the dispersion relations for electromagnetic waves propagating in partially ionized gases immersed in a dc magnetic field. Accurate values of the attenuation constant and phase shift are needed in the design of radio communications systems where waves must propagate through an ionized gas (such as in reentry communications systems), in the design of radar jamming devices used during missile reentry, and in the analytical study of ionospheric propagation phenomena. The numerical solution of the dispersion relations enable the effects of collisionless wave damping, velocity-dependent electron-neutral collisions, and Coulomb encounters to be studied. The attenuation and phase shift of waves propagating through a plasma are dependent upon the signal frequency, plasma temperature, plasma density, degree of ionization, and cross sections for electron scattering. Graphs are presented which enable attenuation constants and phase shifts to be readily evaluated for a very wide range of possible plasma conditions. (Author)

Download or read book Report on Research at AFCRL written by Air Force Cambridge Research Laboratories (U.S.) and published by . This book was released on 1970 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1982 with total page 1282 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.

Download or read book Doctors of Philosophy Harvard University and Radcliffe College with Titles of Their Theses written by Harvard University. Graduate School of Arts and Sciences and published by . This book was released on 1970 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1975 with total page 640 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book American Doctoral Dissertations written by and published by . This book was released on 1971 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Doctors of Philosophy and Doctors of Science with the Titles of Their Theses written by Harvard University. Graduate School of Arts and Sciences and published by . This book was released on 1968 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: Some issues do not include Doctors of science.