Dust Near The Sun Ingrid Mann ∗ and Hiroshi Kimura Institut f¨ ur Planetologie, WWU, M¨ unster, Germany Douglas Biesecker NOAA/SEC, Boulder, CO, USA Bruce T. Tsurutani NASA/JPL, Pasadena, CA, USA Eberhard Gr¨ un † Max-Planck-Institut f¨r Kernphysik, Heidelberg, Germany Bruce McKibben Department of Physics and Space Science Center, University of New Hampshire, Durham, NH, USA Philippe Lamy Laboratoire d’Astrophysique Marseille, France (to be confirmed) Jer-Chyi Liou Lockheed Martin Space Operations, Houston, TX, USA (to be confirmed) Robert M. MacQueen Rhodes College, Memphis, TN, USA Tadashi Mukai Department of Earth and Planetary Sciences, Kobe University, Kobe, Japan Lika Guhathakurta NASA Headquarters, Washington D.C., USA (to be confirmed) Abstract. We review the current knowledge and understanding of dust in the inner solar system. The major sources of the dust population in the inner solar system are comets and asteroids, but the relative contributions of these sources are not quan- tified. The production processes are: Poynting-Robertson deceleration of particles outside of 1 AU, fragmentation of dust due to particle-particle collisions, and direct dust production from comets. The loss processes are: dust collisional fragmentation, sublimation, radiation pressure acceleration, and rotational bursting. These loss processes as well as dust surface processes release dust compounds in the ambient interplanetary medium. Between 1 and 0.1 AU the dust number densities and fluxes can be described by inward extrapolation of 1 AU measurements, assuming radial dependences that describe particles in close to circular orbits. Observations have confirmed the general accuracy of these assumptions for regions within 30 ◦ latitude of the ecliptic plane. The dust densities are considerably lower above the solar poles but Lorentz forces can lift particles of sizes a< 5 µm to high latitudes and produce a random distribution of small grains that varies with the solar magnetic field. Also long-period comets are a source of out-of-ecliptic particles. We show that under present conditions no prominent dust ring exists near the sun. We discuss the recent observations of sungrazing comets. Future in-situ experiments should measure the complex dynamics of small dust particles, identify the contribution of cometary c  2003 Kluwer Academic Publishers. Printed in the Netherlands. dust_1.tex; 7/07/2003; 12:07; p.1