Monday

Steady gamma-ray emission from the quiet Sun has recently been detected up to and beyond 100 GeV. These high-energy gamma rays are supposed to be caused by cosmic rays interacting with the solar photosphere and solar interior. Importantly, beaming as a result of the high energy of the cosmic rays means only those whose direction is reversed before colliding can produce observable gamma rays. Thus, solar magnetic fields must play an important role in turning around the cosmic rays. Previous studies have considered magnetic fields in isolated magnetic flux tubes and large scale fields above the photosphere. However, none of these attempts can explain the gamma rays observed at 100GeV, as the fields were too weak to turn around the cosmic rays. Here we use a model of subsurface horizontal fields between 10% and 100% of the equipartition field strength (calculated with mixing length theory) and show that if these fields exist, they could explain the observed gamma ray flux. This work highlights a new and alternative method for probing the generic structure of magnetic fields beneath the solar surface.