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Gregory A. Benford

Professor Emeritus, Physics & Astronomy
School of Physical Sciences

PH.D., University of California, San Diego, 1967

Phone: (949) 824-5147
Fax: (949) 824-2174
Email: gbenford@uci.edu

University of California, Irvine
4176 Frederick Reines Hall
Mail Code: 4575
Irvine, CA 92697


Research
Interests
Studies of extremely strong turbulence, particularly in astrophysical contexts. Studies of magnetic structures from the galactic center to large scale galactic jets
   
URL www.physics.uci.edu/faculty/benford.html
   
Research
Abstract
Professor Benford earned his Ph.D. from the University of California, San Diego in 1967. He is a member of Phi Beta Kappa, a Woodrow Wilson Fellow, and a consultant for NASA.

This program unites theoretical studies with a parallel experimental program in radiation processes of relativistic electron streams in plasma. Experiments use intense relativistic beams (10 kAmp, 700 keV) propagating in helium plasma. Microwave and atomic spectral (Stark shift) diagnostics measure emission and the underlying turbulent fields. The group also studies the practical methods of high-power microwave emission. Turbulence levels are high, with electric field energy densities comparable with the total thermal energy of the background plasma. Such strong fields demand new theory and sophisticated diagnostics, with fast time resolution (less than ten nanoseconds). This is a new regime-"superstrong" turbulence -- with statistical properties just being explored.

These experiments and coupled theory apply to galactic jets, quasars, and pulsars. Emission by scattering of energetic electrons from plasma turbulence (which the beams themselves produce) can be much more powerful that the familiar single-particle processes such as synchrotron radiation. The extreme variability of quasars recently discovered in radio and optics may arise from such processes. Calculations of expected power and spectra imply that quasars could be powered by flows with less total energy than formerly expected. Much work needs to be done in relating these new, collective radiation mechanisms with both astrophysical and laboratory observations.

Teaching areas include general properties of strong turbulence and radiation, both in experiment and theory. Astrophysical applications of these fundamental areas are also of interest, such as the brilliant radio features (arcs, filaments, threads) recently found at our own galactic center, and their possible links with hypothesized black holes there.
   
Publications Ocean Sequestration of Crop Residue Carbon: Recycling Fossil Fuel Carbon Back to Deep Sediments, STUARTE STRAND, GREGORY BENFORD, Environ. Sci. Technol. 2009, 43, 1000–1007
   
  Fossil AGN jets as ultrahigh-energy particle accelerators, Gregory Benford1 and R. J. Protheroe, Mon. Not. R. Astron. Soc. 383, 663–672 (2008)
   
  Stability of magnetic equilibria in radio bubbles, Gregory Benford, Mon. Not. R. Astron. Soc. 369, 77–82 (2006)
   
  REDUCING SOLAR SAIL ESCAPE TIMES FROM EARTH ORBIT USING BEAMED ENERGY, GREGORY BENFORD AND PAUL NISSENSON, JBIS, Vol. 59, 2006
   
  Stability of magnetic equilibria in radio bubbles, Gregory Benford, Mon. Not. R. Astron. Soc. 369, 77–82 (2006)
   
  Geometric absorption of electromagnetic angular momentum, C. Konz, Gregory Benford, Optics Communications 226 (2003) 249–254, 2003
   
  TO BURY OR TOBURN: OPTIMUM USE OF CROPRESIDUES TO REDUCE ATMOSPHERIC CO2, Robert A. Metzger, Gergory Benford, Martin I. Hoeffert, Correspondence, 2002
   
  Advanced Technology Paths to Global Climate Stability: Energy for a Greenhouse Planet MartinI.Hoffert, Ken Caldeira, Gregory Benford, David R. Criswell, Christopher Green, Howard Herzog, Atul K. Jain, Haroon S. Kheshgi, Klaus S. Lackner, John S. Lewis, H. Douglas Lightfoot, Wallace Manheimer, John C. Mankins, Michael E .Mauel, L. John Perkins, Michael E. Schlesinger, Tyler Volk, Tom M.L.Wigley, Science’s Compass Review, 1 NOVEMBER 2002 VOL 298 SCIENCE www.sciencemag.org
   
  SEQUESTERING OF ATMOSPHERIC CARBON THROUGH PERMANENT DISPOSAL OF CROPRESIDUE, ROBERT A. METZGER And GREGORY BENFORD, 2001
   
  Microwave Beam-Driven Sail Flight Experiments, James Benford, Gregory Benford, Keith Goodfellow, Raul Perez, Henry Harris3,and Timothy Knowles, 2000
   
  Coherent emission and the escape of high brightness temperature radiation in active galactic nuclei, Gregory Benford and H.Lesch, Mon. Not. R. Astron. Soc. 301, 414–418 (1998)
   
  Messaging with Cost-Optimized Interstellar Beacons, James Benford, Gregory Benford, and Dominic Benford, ASTROBIOLOGY, Volume 10, Number 5, 2010, Mary Ann Liebert, Inc., DOI: 10.1089/ast.2009.0393
   
  HAMILTON’S FORCES OF NATURAL SELECTION AFTER FORTY YEARS, Michael R. Rose, Casandra L. Rauser, Gregory Benford, Margarida Matos,3and Laurence D. Mueller1, Perspective, doi:10.1111/j.1558-5646.2007.00120.x
   
  Natural Wormholes as Gravitational Lenses, John G. Cramer,Robert L. Forward, Michael S. Morris, 1994
   
  The Tachyonic Antitelephine, G.A. Benford, D.L. Book, W.A. Newcomb, Phys. Rev. D, Vol. 2, 2, pp 1-3, 1970
   
  Searching for Cost-Optimized Interstellar Beacons, Gregory Benford, James Benford, and Dominic Benford, ASTROBIOLOGY, Volume 10, Number 5, 2010, Mary Ann Liebert, Inc. DOI: 10.1089/ast.2009.0394
   
  Coherent Radiation from Energetic Electron Streams via Collisionless Bremmstrahlung in Electrical Plasma Turbulence, (with J. C. Weatherall) , Astrophys. J. 378, 543 (1991).
   
  Collective Radiation from Jets, Proceedings of the 7th IAP Astrophys. Meeting, Extragalactic Radio Sources from Beams to Jets, Paris, July 2-5 (1991).
   
  Electron Beam Radiation by Collective Compton Boosting of Strong Turbulence, (with J.C. Weatherall), Phys. Fluids B 4 (12) 4111 (1992).
   
  Collective Emission from Rapidly Variable Quasars, Astrophys. J. 391, L59 (1992).
   
  Statistics of Strongly Turbulent Electric Fields, (with X.-L. Zhai), Phys. Fluids B 5 (6) 1914 (1993).
   
   
Link to this profile http://www.faculty.uci.edu/profile.cfm?faculty_id=2097
   
Last updated 07/27/2010