The International Outer Planet Watch

    This is the new webpage for the IOPW program. You will hereafter find links to the former webpages of the program and each discipline. Please send us an email (contact) if you would like to post more information about your research and observations.

    The Program (Archive Page)

    The International Outer Planet Watch is a program for the encouragement and coordination of the study of temporal variations in the Outer Planets. The IOPW coordinates 24-hour coverage of outer planet phenomena when such coverage is needed. It provides a mechanism for the rapid sharing of information to the community of scientists studying the outer planets.

    Scientists working fir the progam belong to several discpines, among which 3 are closely related. This is the "Aurora, Magnetosphere, nad Io Torus" part of the program.


    4 The auroral discipline is specifically concerned with the study of aurorae on Jupiter. "The aurorae on Jupiter are of interest because they allow us to infer the nature of the precipitating energetic particles which cause the auroral radiation. The study of aurorae allows the testing of models of the planetary magnetic field. It permits us to determine the rate of energy deposition from magnetospheric sources. By determining where the aurorae occur, one can ascertain the magnetospheric source regions of the particles and possible causative mechanisms. In particular, it is of significant interest to determine the causes for the differences between the northern and southern aurorae. Finally, particle precipitation near the magnetic poles induces unique chemistry that is important for understanding some aspects of aerosol formation." Russell et al. [external link] (1990)

    Discipline Leader: John Clarke

    Io Torus (Steffl, SWRI)

    The Io torus is a doughnut-shaped ring of gas surrounding Jupiter. The gas originates from the many volcanoes on Io, Jupiter's closest large satellite. The volcanoes on Io spew out sulfur and sulfur dioxide at a rate of 1,000 kg/sec. These particles are ejected into space and are stripped of their electrons (or ionized). The particles (ions) then become trapped in Jupiter's magnetic field. Because the field rotates with the planet, the particles make a complete circle around the planet every ten hours, the rotational period of Jupiter.
    As Io circles around Jupiter and through the plasma torus, an enormous electrical current flows between them. Approximately 2 trillion watts of power is generated. The current follows the magnetic field lines to Jupiter's surface where it creates lightning in the upper atmosphere.