Solar Physics - Science

Observational and theoretical research on the physics of the sun is carried out at Stanford University in several research groups. will link you to the projects carried out by a group of scientists and supporting staff associated with the Center for Space Science and Astrophysics (CSSA) and the Hansen Exerimental Physics Laboratories (HEPL), under the direction of Philip Scherrer (HEPL and the Department of Physics).

The solar group is carrying out research into the Sun from its core to the source of variations in the solar wind.  The group consists of about 35 scientists and staff.  We operate the Wilcox Solar Observatory (WSO) in the Stanford hills, the now retired Michelson Doppler Imager (MDI) on the Solar and Heliosperhic Observatory (SOHO), and the Helioseismic and Magnetic Imager (HMI) on the Solar Dynamics Observatory (SDO). As part of the SDO program we operate the Joint Science Operations Center (JSOC) which provides analysis capability and houses the data archives of SDO HMI and AIA (Atmospheric Imaging Assembly), SOHO/MDI, and WSO.

With Dopplergrams from SDO/HMI we have new opportunities to study the interior with helioseismology.  We are developing new ways of measuring flows, thermal structure, and possibly detecting magnetic fields throughout the solar convection zone out to the photosphere.  We have interests in time scales from the solar cycle to a few minutes.  We are using MHD simulations of the outer convection zone to explore the near surface interaction of waves, magnetic fields, and convective turbulence.  We are using new techniques to measure the meridional flows that are part of the driving forces behind the solar dynamo, new methods to detect near surface motions that order and shred active regions, and methods to detect erupting active regions hours or days before they begin to disrupt the surface or corona.

With magnetograms from HMI both by themselves and in conjunction with coronal images from SDO/AIA we are studying the interaction of changing fields with the coronal plasma with the goal of learning how to estimate probabilities of flares and the initiation of coronal mass ejections (CMEs).  Flares and CMEs are the source of many of the important aspects of space weather.

We are also interested in the solar cycle and its variations from one decade to the next.  Data from the WSO allows comparisons of large scale magnetic fields over nearly four decades.  This data supports examinations of historic data spanning hundreds of years as well as helping to constrain dynamo models to the real Sun.

In addition to data from our three Stanford led solar observing instruments, SDO/HMI, SOHO/MDI, and WSO, we participate in data analysis and interpretation from other ground based programs and space instrumentation.

Please see Solar Physics at Stanford University for detailed information.