Unified Radio And Plasma Wave Experiment

The URAP experiment provides electric field measurements from "DC" to 1 MHz and magnetic field measurements from 0.22 to 450 Hz. These bandwidths permit the study of radio emissions from solar ejecta, interplanetary transients, and planetary magnetospheres and of in situ plasma waves associated with interplanetary shocks, coronal mass ejections, and other transients. The radio observations provide an important remote diagnostic of solar flares and shocks. The plasma wave observations are critical to the understanding of instabilities that exist throughout the interplanetary medium (IPM). Furthermore, analyses of the URAP data permit deriving fundamental characteristics of the solar wind, such as electron density and temperature.

To date, the URAP studies have lead to more than 50 published papers on the in-ecliptic, Jovian flyby, and out-of-ecliptic phases of the Ulysses Mission. In the follow-on Ulysses at Solar Maximum Mission, we will have the opportunity to study the Sun and IPM at the peak of the solar cycle, when they are more active. The remote radio observations will serve an important role in distinguishing and separating multiple solar events, which will be observed as superimposed events at the spacecraft. In situ plasma wave activity will also be significantly enhanced due to the increased number of transients. We are looking forward to the comparison of these observations with those of the WIND WAVES experiment, which has been configured similarly to the URAP experiment, and which will provide a 1 AU baseline for the Ulysses out-of-ecliptic observations.

A list of the current URAP Co-investigators is given below.

  URAP Investigator        Institution
  --------------------------------------------------------------  
  Robert J. MacDowall(PI)  NASA/Goddard Space Flight Center
  Jean-Louis Bougeret      Observatoire de Paris-Meudon
  Patrick Canu             CETP, Velizy, France
  Nicole Cornilleau        CETP, Velizy, France
  Michael Desch            NASA/Goddard Space Flight Center
  Joseph Fainberg          NASA/Goddard Space Flight Center
  Keith Goetz              University of Minnesota
  Melvyn L. Goldstein      NASA/Goddard Space Flight Center
  Christopher C. Harvey    Observatoire de Paris-Meudon
  Sang Hoang               Observatoire de Paris-Meudon
  Michael L. Kaiser        NASA/Goddard Space Flight Center
  Paul J. Kellogg          University of Minnesota
  Alain Lecacheux          Observatoire de Paris-Meudon
  Bent M. Pedersen         Observatoire de Paris-Meudon
  Michael J. Reiner        NASA/Goddard Space Flight Center
  Jean-Louis Steinberg     Observatoire de Paris-Meudon
  Robert G. Stone          NASA/Goddard Space Flight Center