Speaker:
Bob Leamon, Goddard Space Flight Center

Title:
"Little Chunks of Glass in Space: From Optics to Science on SDO"

Abstract:
SDO is NASA's Solar Dynamics Observatory. It is the first mission from the Living With a Star Program, and scheduled for launch in April 2008. In this talk I will cover the SDO mission as a whole, its three instrument suites, and then focus on HMI, the Helioseismic and Magnetic Imager.

Perhaps the biggest improvement SDO offers over previous, or even concurrent, space missions is that its magnetic fields investigation, HMI, offers the ability to determine the vector magnetic field in the solar atmosphere. The ability to calculate the vector field, as opposed to just the line-of-sight component, is critical in understanding the nature, evolution, dynamics and activity of the magnetic field in the solar atmosphere, and thus the effects of Space Weather on our technological society. HMI will do so at high cadence (~90s), and over the entire solar disk.

It does all this with the "little chunks of glass" that I refer to: a Lyot filter with a single tunable element, and two tunable wide-field polarizing Michelson interferometers that split the incoming light into its various constituent polarizations. Software on the ground converts the filtergrams into Doppler motion and reconstructions of the magnetic field. I will also cover on some of the (computational) challenges of those reconstructions.

Host:
Dick Canfield