Astrophysical and Planetary Sciences Colloquium

Tuesday, April 12, 2016 at 4:00pm

JILA Auditorium

Rebecca Centeno Elliott, High Altitude Observatory, National Center for Atmospheric Research

"Polarimetry: Pinning down the Sun's magnetism"

A Pretty Image from the Talk

Abstract:

Magnetism plays a decisive part in the structure, dynamics and energy budget of the Sun’s atmosphere; it is at the core of the Solar Cycle and behind the origin of Space Weather; it provides efficient means for storage, transportation and release of energy. Magnetic fields from the Sun draw pathways throughout the interplanetary medium, magnetically linking the entire Solar System. In order to better comprehend and more precisely forecast the Sun’s behavior, and how it may affect us, we need to disentangle the elusive nature of its magnetic forces. The intensity and polarization of the light emitted by the Sun carry clues about its physical properties, and in particular, its magnetism. The theory of radiative transfer of polarized light allows us to exploit polarimetric measurements to their full potential, and decipher the information encoded in the radiation. I will review how we use these techniques for remote sensing of magnetic fields on the Sun and other stars, and I’ll delve into the challenges and opportunities that we face looking towards NSO’s Daniel K. Inouye Solar Telescope.

Figure above: Magnetic fields seen at the smallest scales on the Sun's Photosphere. Active regions on the Sun emerge, not as a whole, but in small bundles that pile up magnetism on the surface and aggregate into stronger concentrations, giving rise to sunspots. This figure shows the magnetic topology of one of these individual emergence processes inside an incipient active region. The gray-scale background shows the longitudinal component of the magnetic field (white and black pointing towards and away from the observer, respectively), whilst the headless arrows represent the transverse component of the magnetic field vector. These data were obtained by the Imaging Magnetograph Experiment (IMaX) on board the ballon-borne mission Sunrise II.

 

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