John T Dawson

US Patent:

57809712, Jul 14, 1998

Filed:

Jun 6, 1994

Appl. No.:

8/254410

Inventors:

John M. Dawson - Pacific Palisades CA
Warren B. Mori - Hermosa Beach CA
Chih-Hsiang Lai - So. Pasadena CA
Thomas C. Katsouleas - Malibu CA

Assignee:

Univ. of So. Calif. - Los Angeles CA
The Regents of the Univ. Univ. of Calif. - Oakland CA

International Classification:

H03B 710
H03B 1700

US Classification:

315 39

Abstract:

Method and apparatus for generating radiation of high power, variable duration and broad tunability over several orders of magnitude from a laser-ionized gas-filled capacitor array. The method and apparatus convert a DC electric field pattern into a coherent electromagnetic wave train when a relativistic ionization front passes between the capacitor plates. The frequency and duration of the radiation is controlled by the gas pressure and capacitor spacing.

US Patent:

42130433, Jul 15, 1980

Filed:

Jul 20, 1977

Appl. No.:

5/817328

Inventors:

John M. Dawson - Pacific Palisades CA

Assignee:

TRW Inc. - Redondo Beach CA

International Classification:

B01D 5944
H01J 2700

US Classification:

250283

Abstract:

A plasma isotope separation process and apparatus. The plasma must be generated and moved into an excitation region for the differential heating of a selected isotope. This motion is accomplished by a crossed magnetic and electric field whereby charged particles move normal to the direction of both fields. The plasma is generated by electrons liberated from hot filaments and the electric field is generated by a plurality of electrodes forming an anode for providing an electric field in a desired direction. An alternating electric voltage may additionally be imparted to the anode to generate an alternating electric field, thereby to differentially excite the isotope of the plasma.

US Patent:

40597610, Nov 22, 1977

Filed:

Feb 17, 1976

Appl. No.:

5/658566

Inventors:

John Myrick Dawson - Pacific Palisades CA

Assignee:

TRW Inc. - Redondo Beach CA

International Classification:

H01J 3924

US Classification:

250287

Abstract:

One of the isotopes of an element having several isotopes can be separated from the others in a dense, neutral plasma. Thus initially a neutral plasma is prepared including the element in question. This may consist of positive ions and negative electrons or alternatively of positive and negative ions, or else of a mixture of positive ions, negative ions and electrons. The plasma may then be injected into a magnetic field or may be generated in the field where more energy is imparted to a selected isotope than to the others. Finally, the isotopes are separated from each other on the basis of their differential energies. For example, the selected isotope may be given more energy than the others by stimulating it within the plasma at its resonant frequency which may be close to the cyclotron frequency, either by an electric field or by a magnetic field. In order to excite the other isotope, a different resonant frequency is required which depends on the plasma density, the relative concentration of electrons if the plasma contains electrons, the strength of the magnetic field, the ratio of charge to mass of the isotope, and possibly on the physical parameters of the plasma apparatus itself, such as the ratio of the length of the plasma column to its radius. The more energetic isotope may be separated by energy dependent chemical reactions, it may be collected by a positively biased probe or else the isotopes may be separated from each other by magnetic fields or in various other ways.

US Patent:

49756559, Dec 4, 1990

Filed:

Jun 14, 1989

Appl. No.:

7/366879

Inventors:

John M. Dawson - Pacific Palisades CA
Scott C. Wilks - Santa Monica CA
Warren B. Mori - Hermosa Beach CA
Chandrasekhar J. Joshi - Santa Monica CA
Andrew M. Sessler - Oakland CA

Assignee:

Regents of the University of California - Oakland CA

International Classification:

H01S 300
H03F 700

US Classification:

330 43

Abstract:

Photons of an electromagnetic source wave are frequency-upshifted as a plasma is rapidly created around the path of this propagating source wave. The final frequency can be controlled by adjusting the gas density. A controlled time-varying frequency (chirped) pulse can be produced by using a controlled spatially varying gas density. The plasma must be created in a time which is short compared to the transit time of the light through the plasmas region. For very fast creation over one to at most a few light periods of an overdense plasma, static magnetic fields with short wavelengths are created.

US Patent:

40816770, Mar 28, 1978

Filed:

Feb 17, 1976

Appl. No.:

5/658567

Inventors:

John Myrick Dawson - Pacific Palisades CA

Assignee:

TRW Inc. - Redondo Beach CA

International Classification:

H01J 3934

US Classification:

250290

Abstract:

One of the isotopes of an element having several isotopes can be separated from the others in a dense, neutral plasma. Thus initially a neutral plasma is prepared including the element in question. This may consist of positive ions and negative electrons or alternatively of positive and negative ions, or else of a mixture of positive ions, negative ions and electrons. The plasma may then be injected into a magnetic field or may be generated in the field where more energy is imparted to a selected isotope than to the others. Finally, the isotopes are separated from each other on the basis of their differential energies. For example, the selected isotope may be given more energy than the others by stimulating it within the plasma at its resonant frequency which may be close to the cyclotron frequency, either by an electric field or by a magnetic field. In order to excite the other isotope, a different resonant frequency is required which depends on the plasma density, the relative concentration of electrons if the plasma contains electrons, the strength of the magnetic field, the ratio of charge to mass of the isotope, and possibly on the physical parameters of the plasma apparatus itself, such as the ratio of the length of the plasma column to its radius. The more energetic isotope may be separated by energy dependent chemical reactions, it may be collected by a positively biased probe or else the isotopes may be separated from each other by magnetic fields or in various other ways.

US Patent:

H5541, Dec 6, 1988

Filed:

Mar 3, 1982

Appl. No.:

6/354418

Inventors:

John M. Dawson - Pacific Palisades CA
Harold P. Furth - Princeton NJ
Fred H. Tenney - Princeton NJ

Assignee:

The United States of America as represented by the United States
Department of Energy - Washington DC

International Classification:

G21B 100

US Classification:

376107

Abstract:

Method for producing fusion power wherein a neutral beam is injected into a toroidal bulk plasma to produce fusion reactions during the time permitted by the slowing down of the particles from the injected beam in the bulk plasma.

US Patent:

49375326, Jun 26, 1990

Filed:

Sep 14, 1988

Appl. No.:

7/244485

Inventors:

John M. Dawson - Pacific Palisades CA
Scott C. Wilks - Santa Monica CA

Assignee:

The Regents of the University of California - Berkeley CA

International Classification:

H01J 746
H01S 309

US Classification:

330 43

Abstract:

Photons of a laser pulse have their group velocity accelerated in a plasma as they are placed on a downward density gradient of a plasma wave of which the phase velocity nearly matches the group velocity of the photons. This acceleration results in a frequency upshift. If the unperturbed plasma has a slight density gradient in the direction of propagation, the photon frequencies can be continuously upshifted to significantly greater values.

US Patent:

39611973, Jun 1, 1976

Filed:

Aug 21, 1974

Appl. No.:

5/499221

Inventors:

John M. Dawson - Los Angeles CA

Assignee:

The United States of America as represented by the United States Energy
Research and Development Administration - Washington DC

International Classification:

H01S 400
G21G 400

US Classification:

250493

Abstract:

Apparatus and method for producing coherent secondary x-rays that are controlled as to direction by illuminating a mixture of high z and low z gases with an intense burst of primary x-rays. The primary x-rays are produced with a laser activated plasma, and these x-rays strip off the electrons of the high z atoms in the lasing medium, while the low z atoms retain their electrons. The neutral atoms transfer electrons to highly excited states of the highly striped high z ions giving an inverted population which produces the desired coherent x-rays. In one embodiment, a laser, light beam provides a laser spark that produces the intense burst of coherent x-rays that illuminates the mixture of high z and low z gases, whereby the high z atoms are stripped while the low z ones are not, giving the desired mixture of highly ionized and neutral atoms. To this end, the laser spark is produced by injecting a laser light beam, or a plurality of beams, into a first gas in a cylindrical container having an adjacent second gas layer co-axial therewith, the laser producing a plasma and the intense primary x-rays in the first gas, and the second gas containing the high and low atomic number elements for receiving the primary x-rays, whereupon the secondary x-rays are produced therein by stripping desired ions in a neutral gas and transfer of electrons to highly excited states of the stripped ions from the unionized atoms. Means for magnetically confining and stabilizing the plasma are disclosed for controlling the direction of the x-rays.

Author:

John Philip Dawson

ISBN #:

0300024460

Author:

John P. Dawson

ISBN #:

0882770470

Author:

John P. Dawson

ISBN #:

0882775529

Author:

John Keith Dawson

ISBN #:

0114107742

Author:

John J. Dawson

ISBN #:

0806616628

Author:

John Dawson

ISBN #:

0307240797

Author:

John Dawson

ISBN #:

0313202605

Author:

John Dawson

ISBN #:

0631207309