IRIS Movie of the Day
At least once a week a movie of the Sun taken by NASA's Interface Region Imaging Spectrograph (IRIS) is posted by one of the scientists operating the instrument.
Up and down
Credit: IRIS, LMSAL/NASA
The Sun's magnetic field drives much of the activity in the solar atmosphere that IRIS observes. In this example we see cold plasma that is expelled violently. Studying this type activity is important for understanding the role of the magnetic field in releasing energy in the solar atmosphere. The expulsion of cool plasma is part of a so-called spray surge. It is most likely driven by a process called magnetic reconnection. Magnetic reconnection is a change in the magnetic field configuration that can lead to strong acceleration of plasma as well as heating of plasma. After the plasma is expelled, it slides back downward along the magnetic field. Above these surges, most likely due to sporadic heating due to these violent processes, coronal rain is forming. Coronal rain is formed as a result of a rapid cooling of million degree plasma that falls back to the Sun, again, following the magnetic field lines.