Dr. Roberts is actively involved in research on interplanetary turbulence and the modeling of nonlinear processes. His observational and MHD simulation efforts in these areas have clarifed the role of nonlinear processes in the heliosphere, in particular showing that such processes are necessary to explain the observations and tracing the evolution of the interplanetary turbulence from 0.3 to 20 AU. He has used observations and simulations to place strong constraints on the role of waves in the acceleration and heating of the solar wind. He is the author of over 100 publications in the above and other areas. Dr. Roberts is Principal and Co-Investigator on NASA Supporting Research and Technology grants to perform multispacecraft studies of the heliosphere and to use MHD simulations to understand the observations. He was a co-investigator on Goddard's Space Physics Theory Program grant from NASA, as well as on other supporting research and technology grants. He has also been Principal Investigator on NASA grants to study advanced visualization methods for displaying, browsing, analyzing, and retrieving large data sets from both observations and simulations; the methods include stereoscopic techniques on desktop workstations, as well as a Java3D-based interactive application ("ViSBARD") that allows the 3-D viewing of data along spacecraft orbits. More recently he has been funded by NASA to develop a "Virtual Space Physics Observatory" (VSPO) that provides access to the wide variety of space and solar physics data needed to address global Sun-Earth connection problems. Related to this, he is now serving as the Heliophysics Data Envirionment Program Scientist at NASA Headquarters (see the NASA HPDE site).
Positions and Appointments
1983-1985 Postdoctoral Associate at Washington University in St. Louis
1986-1988 NAS/NRC Postdoctoral Research Associate, GSFC
Education
B.S. and Ph.D. degrees from the Massachusetts Institute of Technology in 1973 and 1983, respectively.
Publications
"Nature and Evolution of Magnetohydrodynamic Fluctuations in the Solar Wind: Voyager Observations," D. A. Roberts, L. W. Klein, M. L. Goldstein, and W. H. Matthaeus, Journal of Geophysical Research, 92, 11,021, 1987.
"Origin and Evolution of Fluctuations in the Solar Wind: Helios Observations and Helios- Voyager Comparisons," D. A. Roberts, M. L. Goldstein, L. W. Klein, and W. H. Matthaeus, Journal of Geophysical Research, 92, 12,023, 1987.
"Turbulent Polar Heliospheric Magnetic Fields," D. A. Roberts, Geophysical Research Letters, 17, 567, 1990.
"Turbulence and Waves in the Solar Wind," D. A. Roberts and M. L. Goldstein, Reviews of Geophysics, 29(S), 932, 1991.
"Is There a Strange Attractor in the Magnetosphere?," D. A. Roberts, Journal of Geophysical Research, 96, 16031, 1991.
"MHD Simulation of the Radial Evolution and Stream Structure of Solar Wind Turbulence," D. A. Roberts, S. Ghosh, M. L. Goldstein, and W. H. Matthaeus, Physical Review Letters, 67, 3741, 1991.
"Nonequilibrium, Large-Amplitude MHD Fluctuations in the Solar Wind," D. A. Roberts and M. J. Wiltberger, Journal of Geophysical Research, 100, 3,405, 1995.
"Nonlinear Evolution of Interplanetary Alfvénic Fluctuations with Convected Structures," D. A. Roberts, S. Ghosh, and M. L. Goldstein, Geophysical Research Letters, 23, 591, 1996.
"The Nature of the Solar Wind," D. A. Roberts, K. W. Ogilvie, and M. L. Goldstein, Nature, 381, 31, 1996.
"In Situ Measurement Requirements for a Solar Probe," D. A. Roberts and J. Gosling, Invited Moderator Review in Scientific Basis for Robotic Exploration Close to the Sun, S. Habbal, ed., New York, AIP, p. 3, 1996.
"Quasi-Two-Dimensional MHD Turbulence in Three-Dimensional Flows," D. A. Roberts, M. L. Goldstein, A. Deane, and S. Ghosh, Physical Review Letters, 82, 548, 1999.
"A kinematic analysis of the role of velocity shear in expanding plasmas," D. A. Roberts and S. Ghosh, Journal of Geophysical Research, 104, 22,395, 1999.
"Origin and Dynamics of the Heliospheric Plasma and Current Sheets," D. A. Roberts, P. Keiter, and M. L. Goldstein, Journal of Geophysical Research, 110, DOI: 10.1029/2004JA010541, 2005.
"Power Spectrum of Small Scale Turbulent Velocity Fluctuations in the Solar Wind," Podesta, J. J., D. A. Roberts, and M. L. Goldstein, Journal of Geophysical Research, 111, DOI: 10.1029/2006JA011834, 2006
"Solar Wind Structure Suggested by Bimodal Correlations of Solar Wind Speed and Density between the Spacecraft SoHO and Wind," K. W. Ogilvie, M. A. Coplan, D. A. Roberts, F. Ipavich, Journal of Geophysical Research, in press, 2007.
"Spectra of polar heliospheric fields and implications for field structure," D. A. Roberts, J. Giacalone, J. R. Jokipii, M. L. Goldstein, and T. D. Zepp, Journal of Geophysical Research, in press, 2007.
