The Dynamic Solar Magnetic Field

While the sun is well known as the overwhelming source of visible light in our solar system, a substantial part of its influence is driven by some aspects less visible to human perception - the magnetic field. In this visualization, the sphere represents the solar photosphere, with neutral grey indicating a magnetic field of near zero intensity, black representing a magnetic field pointing INTO the sun (south or negative polarity) and white representing a magnetic field pointing OUT of the sun (north or positive polarity). We see that these magnetic regions often appear in nearby pairs of opposite polarities - which in visible light would often correspond to a pair of sunspots. Using this measured magnetic field on the photosphere, combined with mathematical models based on Maxwell’s equations and plasma physics, we can construct how the magnetic field would look above the photosphere. Here, the white magnetic field lines are considered ’closed’. They move up, and then return to the solar surface. We often see these closed lines associated with pairs of active regions on the sun. The green and violet lines represent field lines that are considered ’open’. Green represents positive magnetic polarity, and violet represents negative polarity. These field lines do not connect back to the sun but with more distant magnetic fields in space. Here we build one of the simpler magnetic field models, called Potential Field Source Surface or PFSS, to construct how the magnetic ’lines of force’ might look above the sun. The PFSS model represents the simplest and most steady magnetic field possible, though here we sample the field each day to illustrate the slow changes of the magnetic structure over time, in this case between January 1, 2011 through December 30, 2014. Visualizer: Tom Bridgman (lead) For more information or to download this public domain video, go to #23751