Robert Richard

Robert Richard
Researcher
Research Geophysicist, Magnetospheric Physicist

Office: 3869 Slichter Hall
Phone: (310) 825-1881
E-Mail: [javascript protected email address]

Educational Background: 

Ph.D. in Physics, University of California, Los Angeles, 1988

AB in Physics, University of California, Berkeley, 1981
 

Positions Held: 

2011 (July) - present Research Geophysicist, Department of Physics & Astronomy, Institute of Geophysics & Planetary Physics, University of California, Los Angeles

1997 - 2011 (July) Associate Research Geophysicist, Institute of Geophysics & Planetary Physics, University of California, Los Angeles

1991 (April) - 1997 Assistant Research Geophysicist, Institute of Geophysics & Planetary Physics,, University of California, Los Angeles

1989 (July) - 1991 (March) Research Associate, Thayer School of Engineering, Dartmouth College, Hanover, NH

1988 (Sept.) - 1989 (July) Assistant Research Geophysicist, Institute of Geophysics & Planetary Physics, University of California, Los Angeles

1985 - 1988 (Sept.) Research Assistant, Institute of Geophysics & Planetary Physics,, University of California, Los Angeles

1982 - 1984 Teaching Assistant, Department of Physics, University of California, Los Angeles

1983 (summer) Research Assistant, Lawrence Laboratory, University of California, Berkeley

1982 (Jan.) - 1982 (Apr.) Technical Assistant, Lawrence Laboratory, University of California, Berkeley

 

Research Interest: 

Dayside Particle Entry and Acceleration

The solar wind is a stream of charged particles that flows from the Sun to the Earth along with solar magnetic fields coupled to the particles (the interplanetary magnetic field or IMF).  These fields and particles interact with the Earth’s magnetosphere.  Depending on the relative orientations of the IMF and the Earth’s magnetic field, the process of reconnection can take place, the result of which is that some of the energy of the magnetic field is transferred to the particles.  As a result of this process electrons can precipitate into the upper atmosphere of the Earth, resulting in visible auroras at high latitudes.

 Our specific goal is to understand how solar wind ions enter the magnetosphere and the processes that determine their energies.  One example of the features we study is latitude-energy dispersion.  As spacecraft pass through the high latitude dayside region, the energies of particles changes in a way that reflects physical processes active at the dayside; including reconnection.  The process begins with observations made by spacecraft sunward of the magnetosphere.  These observations are used to conduct magnetohydrodynamic (MHD) simulations of the magnetosphere by providing driving conditions at the sunward boundary of the simulations.  MHD simulations provide the time evolution of electric and magnetic fields in the magnetosphere and adjacent regions.  The next step is to follow a large number of test particle ions (a technique called large scale kinetics or LSK) in the time-dependant fields produced by the MHD simulations.  simulations.  Idealized cases can also be studied to understand basic physical processes.

Solar Energetic Particles

The Earth’s magnetosphere is the region of space dominated by the Earth’s internal magnetic field.  Particles that are accelerated to high energies by disturbances originating at the Sun, called Solar Energetic Particles (SEPs), can enter the magnetosphere, leading to intense particle fluxes.  These particles can, at times, become trapped in the inner magnetosphere for time intervals ranging from hours to months, where they can affect satellites.  We are studying SEP entry and energization in Earth’s magnetosphere by using numerical simulations.

 The process begins with observations made by spacecraft sunward of the magnetosphere during a magnetic storm with high SEP flux.  These observations are used to conduct MHD simulations of the magnetosphere. The next step is to perform LSK simulations in the time-dependant fields produced by the MHD simulations.  The results can be combined with measurements of SEPs within and outside of the magnetosphere to better understand the physical processes involved.

 

Selected Publications: 

Richard, R. L., M. Ashour-Abdalla, and F. V. Coroniti (1993), Narrow-band electrostatic noise generated by an electron velocity space hole, J. Geophys. Res., 98, 11,359.

Richard, R. L., R. J. Walker, and M. Ashour-Abdalla (1994), The population of the low latitude boundary layer by solar wind ions when the interplanetary field is northward, Geophys. Res. Lett., 21, 2455.

Richard, R. L., L. M. Zelenyi, and M. Ashour-Abdalla, Modeling the linear transient response of the magnetotail to variations in the plasma mantle, J. Geophys. Res., 100, 21,835, 1995.

Richard, R. L., R. J. Walker, T. Ogino, and M. Ashour-Abdalla (1997), Flux ropes in the magnetotail: Consequences for ion populations, Adv. Space Res., 20(4/5), 1017.

Richard, R. L., M. El-Alaoui, M. Ashour-Abdalla and R. J. Walker (2002), Interplanetary magnetic Field Control of the Entry of Solar Energetic Particles into the Magnetosphere, J. Geophys. Res., 107 (A8), 10.1029/2001JA000099.

El-Alaoui, M., R. L. Richard, M. Ashour-Abdalla, and M.W. Chen, Low Mach number bow shock locations during a magnetic cloud event: Observations and magnetohydrodynamic simulations, Geophys. Res. Lett., 31, L03813, doi:10.1029/2003GL018788, 2004.

Richard, R. L., M. El-Alaoui, M. Ashour-Abdalla and R. J. Walker (2009), Modeling the Entry and Trapping of Solar Energetic Particles in the Magnetosphere during the November 24-25, 2001 Storm, J. Geophys. Res., 114, A04210, doi:10.1029/2007JA012823.

Ashour-Abdalla, M., M. El-Alaoui., M. Goldstein , M. Zhou , Dr. D. Schriver , R. Richard , R. Walker , M. G. Kivelson , K. Hwang (2011), Observations and Simulations of Nonlocal Acceleration of Electrons in Magnetotail Magnetic Reconnection Events, Nature Physics, doi10.1038nphys1903