**J.T. Hoeksema**, R.I. Bush, P.H. Scherrer

W.W. Hansen Experimental Physics Laboratory, HEPL Annex B213, Stanford University, Stanford, CA 94305-4085

C. Heck, N. Hurllburt, A. Title

Lockheed Martin Palo Alto Research Laboratory 91-30/252, 3251 Hanover St., Palo Alto, CA 94304

The Solar Oscillations Investigation Michelson Doppler Imager (SOI/MDI) on SOHO has measured the solar photospheric magnetic field with 4" resolution over the whole disk nearly every 96 minutes since April 1996. This unprecedented continuous sequence of frequent, uniform quality magnetograms provides a striking view of the continuous emergence and evolution of flux over the visible surface of the Sun near solar minimum. Since evolving solar magnetic fields drive the variations of the corona and solar wind that affect the solar-terrestrial environment, knowledge of the rapidly evolving photospheric field provides a crucial input for forecasting conditions in the corona, heliosphere, and geospace.

A few magnetic images are available each day within hours of observation through the SOHO web site at http://sohowww.nascom.nasa.gov/. These are used for planning and forecasting purposes. The remainder are generally available within a couple of weeks. From time to time intensive magnetic campaigns are run that provide observations as often as once each minute for up to 8 hours. These can be taken with either the full disk resolution or with 0.6" pixels in a limited region near the center of the disk. The SOI project welcomes collaborations. More information can be found at http://soi.stanford.edu/.