The Cassini radio and plasma wave investigation is designed to study radio emissions, plasma waves, thermal plasma, and dust in the vicinity of Saturn. Three nearly orthogonal electric field antennas are used to detect electric fields over a frequency range from 1 Hz to 16 MHz, and three orthogonal search coil magnetic antennas are used to detect magnetic fields over a frequency range from 1 Hz to 12 kHz. A Langmuir probe is used to measure the electron density and temperature. Signals from the electric and magnetic antennas are processed by five receiver systems: a high frequency receiver that covers the frequency range from 3.5 kHz to 16 MHz, a medium frequency receiver that covers the frequency range from 24 Hz to 12 kHz, a low frequency receiver that covers the frequency range from 1 Hz to 26 Hz, a five-channel waveform receiver that covers the frequency range from 1 Hz to 2.5 kHz in two bands, 1 Hz to 26 Hz and 3 Hz to 2.5 kHz, and a wideband receiver that has two frequency bands, 60 Hz to 10.5 kHz and 800 Hz to 75 kHz. In addition, a sounder transmitter can be used to stimulate plasma resonances over a frequency range from 3.6 kHz to 115.2 kHz. Fluxes of micron-sized dust particles can be counted and approximate masses of the dust particles can be determined using the same techniques as Voyager. Compared to Voyagers 1 and 2, which are the only spacecraft that have made radio and plasma wave measurements in the vicinity of Saturn, the Cassini radio and plasma wave instrument has several new capabilities. These include (1) greatly improved sensitivity and dynamic range, (2) the ability to perform direction-finding measurements of remotely generated radio emissions and wave normal measurements of plasma waves, (3) both active and passive measurements of plasma resonances in order to give precise measurements of the local electron density, and (4) Langmuir probe measurements of the local electron density and temperature. With these new capabilities, it will be possible to perform a broad range of studies of radio emissions, wave-particle interactions, thermal plasmas and dust in the vicinity of Saturn.
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The authors would like to express their thanks to R. Barrie, R. Brechwald, A. Cooper, M. DeBower, R. Huff, R. Johnson, S. Kutcher, M. Mitchell, B. T. Pham, J. Phillips, R. Randall, S. Remington, W. Robison, W. Schintler, J. Schwartz, P. Sheyko, D. Tomash, and E. Williams at the University of Iowa, for their role in designing, assembling, and testing the instrument; to P. Fédou, N. Monge, D. Carriere, J. M. Boulben, R. Knoll, J. P. Mengue, C. Gueriau, L. Belmon, G. Nicol, A. Rapin, and L. Friel at the Observatoire de Paris, for their role in designing, assembling, and testing the high frequency receiver; to P. Chauveau and S. Louis at CETP, for their role in designing, assembling, testing of the search coil magnetic sensors, and to V. Bouzid for her role in software development; to H. Gunnarsson, B. Holback, S.-E. Jansson, and H. Thomas at the Swedish Institute of Space Physics, for their role in designing, assembling, and testing the Langmuir probe; to I. Willis at the University of Sheffield, for his role in the software development; to R. Kramer of Orbital Sciences Corporation for his role in constructing the electric antennas; to W. Fawcett, K. Breitenbach, M. Lane, R. Poynter, P. Liewer, and S. J. Bolton at the Jet Propulsion Laboratory for their role in coordinating the experiment integration and testing at the Jet Propulsion Laboratory. Special thanks are also given to R. Spehalski, R. Draper, T. Gavin, and E. Miner at the Jet Propulsion Laboratory for their help in solving many of the spacecraft interface problems associated with a complex instrument of this type. The U.S. funding for the instrument development, assembly, and testing was provided by NASA through contract 959515 through the Jet Propulsion Laboratory. The post-launch U.S. mission operations and data analysis phase of this investigation is supported by NASA through contract 961152, also through the Jet Propulsion Laboratory. The Observatoire de Paris contributions were supported by the Centre National d’etudes Spatiales. The CETP contributions are supported by Centre National d’etudes Spatiales under contract 204.