A day after the US celebrates Independence Day with fireworks, NASA will launch a mission to investigate fireworks of an entirely different sort — the intense, chaotic magnetic environment of the Sun’s chromosphere.
The Solar Ultraviolet Magnetograph Investigation, or SUMI — the result of a partnership between NASA, the European Space Agency, and the Japanese Aerospace Exploration Agency — will reportedly provide a close vantage point for observing our nearest star. The mission, say astronomers, will allow for observation of a different part of the electromagnetic spectrum, one which we know little about. To measure magnetic fields in the chromosphere, SUMI will observe the ultraviolet (UV) light emitted from two types of atoms on the sun, Magnesium 2 and Carbon 4.
The sounding rocket mission will be launched from White Sands Missile Range in New Mexico and will serve to validate the performance of the instruments and provide additional data that could help to improve the design. Depending on the success of this and future missions, it could also lay the ground for a future satellite-based observation mission, say scientists.
“What’s novel with this instrument is that it observes ultraviolet light, when all the others look at infrared or visible light,” says Jonathan Cirtain, a solar scientist at NASA’s Marshall Space Flight Centre and the principal investigator for SUMI. “Those wavelengths of light correspond to the lowest levels in the sun’s atmosphere, but SUMI will look at locations higher in the chromosphere.”
The chromosphere is a layer of the Sun’s atmosphere that is sometimes visible during solar eclipses as a thin band of color surrounding the darkened solar disk. This layer becomes very energetic as it approaches its upper boundary where it feeds into the corona, the layer largely responsible for violent solar activity such as solar flares and Coronal Mass Ejections and by far the hottest region of the Sun that we directly observe, with a temperature in excess of a million degrees Celsius.
Magnetic fields lie at the heart of the Sun’s ability to generate such phenomena and will give us a better understanding of how they are generated and how to predict them.
During its brief sounding rocket flight, which will carry the instrument 125-185 miles into Earth’s atmosphere, SUMI will collect just five minutes worth of data. Employing a technology similar to that used in polarized sunglasses, SUMI will determine the intensity of emission for multiple degrees of polarization. This will permit characterization of the strength and direction of the magnetic field at several altitudes in the solar atmosphere, as the degree of polarization for the emission source is dependent on the direction and strength of the field.