Sol! Solar Astrophysics

* Overview: The Solar Corona and Solar Wind

I work with the Ultraviolet Coronagraph Spectrometer (UVCS) group connected with the SOHO (Solar and Heliospheric Observatory) mission. The overall goal of this project is to obtain an empirical description of the extended solar corona and wind, which will lead to better theoretical understanding of how the solar wind is accelerated.

There are many introductory WWW pages out there that explain what we know about the Sun, and how it affects us here on Earth. To begin, I'll link to several of the best of these pages:


The objective of the UVCS investigation is to answer certain fundamental questions concerning acceleration processes in the corona and their relationship to solar wind properties near the earth. These are some of the questions that UVCS is addressing (from the UVCS Experiment Handbook):

Since one of the primary topics of my Ph.D. thesis work was radiative transfer, the first thing I did upon starting to work for the UVCS group was to spend time understanding the actual diagnostics (ultraviolet emission lines, white-light polarization, etc.) that are used to infer things like density, velocity, and temperature in the corona. I wrote several technical notes that contain bottom-up derivations of how these diagnostics work (they are linked on my miscellaneous and unpublished work page).

I also spend a lot of time doing theoretical modeling of the non-equilibrium plasma state of the extended corona. We hope to understand the anisotropic ion temperatures and high outflow velocities observed by UVCS in terms of detailed models of the kinetic velocity distributions and wave fluctuation spectra. More recently (post-2003), this work has taken a turn into the study of magnetohydrodynamic turbulence . . .

(The left image is from van Ballegooijen 1986; the right image is from simulatations performed by the Bartol group)

Other papers, presentations, and links:

Many other online documents and news items are listed on the UVCS Home Page.

* Solar and Space Physics Links

<- GO BACK to Steven Cranmer's Home Page, or to the Harvard-Smithsonian CfA Home Page.