ATMoB Business Meeting Online (Zoom)
High-Altitude Instrumentation for Infrared Observations of the Solar Corona – Dr. Jenna Samra's Presentation
The solar corona is notable for its million-degree temperatures and its violent eruptions, but we don’t understand exactly how coronal heating takes place, and we can’t predict precisely when solar activity will occur. Both are controlled by the corona’s magnetic field, which is extremely difficult to measure. High-altitude infrared remote sensing is a promising method for coronal magnetometry that is just now beginning to be explored. This talk presents results from Smithsonian’s new Airborne Infrared Spectrometer (AIR-Spec) and outlines concepts for future airborne and balloon-based spectrometers and spectro-polarimeters.
AIR-Spec was commissioned during the August 21, 2017 total solar eclipse, when it observed five infrared coronal emission lines from the NSF Gulfstream V research jet. These magnetically sensitive emission lines of highly ionized magnesium, silicon, sulfur, and iron are promising candidates for future observations of the coronal magnetic field, and their characterization is an important first step toward developing the next generation of instrumentation for coronal magnetometry. The second AIR-Spec research flight took place during the July 2, 2019 total solar eclipse across the south Pacific. Higher sensitivity and reduced jitter enabled more precise measurements of emission line properties and plasma density, temperature, and line-of-sight velocity up to one solar radius from the solar limb. Atmospheric absorption was significant, even at altitude, and atmospheric modeling was required to extract accurate line intensities.
AIR-Spec is an imaging spectrometer that measures light over a 1.55 solar radius field of view in three spectral passbands between 1.4 and 3 microns. The package includes an image stabilization system, feed telescope, cryogen-cooled grating spectrometer, and white light imager. The successful eclipse missions overcame a number of engineering challenges, centered around maintaining adequate resolution and signal-to-noise ratio in a compact and inexpensive package on a moving platform. AIR-Spec is a pathfinder for future infrared spectrometers and spectro-polarimeters, including a balloon-based coronagraph that will measure the global coronal magnetic field and an airborne spectrometer that will survey the infrared emission corona during a future eclipse.
About the speaker:
As a scientist at Smithsonian Astrophysical Observatory (SAO), Jenna Samra develops optical instrumentation for scientific investigations of the solar corona and earth's atmosphere. Her recent PhD thesis focused on the creation of AIR-Spec, an airborne spectrometer that observes the infrared corona during total solar eclipses. Jenna is the instrument scientist on another airborne infrared spectrometer, MethaneAIR, which measures atmospheric methane. She has designed solar instruments for sub-orbital rockets, high-altitude balloons, and the International Space Station, and she is currently developing a stabilized platform to enable solar and atmospheric remote sensing experiments from the Gulfstream V. Before joining SAO as a graduate student in 2014, she worked at MIT Lincoln Laboratory on the development of environmental monitoring sensors. Jenna obtained BS and MS degrees in Electrical Engineering from Penn State in 2006 and 2008 and received her PhD in Applied Physics from Harvard University in 2018.