Coronal Magnetography Of Solar Active Regions Via 3D Modeling And Radio Imaging Spectroscopy

The Principal Investigator (PI) and his team will investigate the use and interpretation of radio imaging spectroscopy observations of solar active regions through advanced theory development and 3D modeling of gyroresonance (GR) and free-free emission. The GR process permits radio emission to provide direct measurements of magnetic field strength and direction in the solar corona, and so supplies the key to understanding the basic mechanisms underlying all of solar activity. This team''s recent work in comparing spatially and spectrally resolved radio emission with magnetic field extrapolations of photospheric magnetograms and other data has suggested that an extension of existing theory to non-Maxwellian particle distributions may be needed to account for the observed altitudes of solar radio sources. The PI therefore will develop a comprehensive modeling framework for flaring loops that is capable of reproducing physically realistic solar atmospheric structure, including distributions of non-thermal particles.

The PI''s existing tools have already successfully calculated both gyrosynchrotron (GS) radio emission and hard X-ray emission for forward-fitting microwave and X-ray observations of solar flares. Here, the team plans to modify this general framework to model GR emission. This requires a sEnvironmental Protection Agencyrate development effort to deal with specific issues arising from the GR process, including grid resolution problems, the treatment of the process in spherical coordinates to deal with the large fields of view involved in active region emission, and the development of a consistent way to specify ambient solar plasma temperature and density in addition to the magnetic field.

In this effort, the PI''s team will develop user-friendly software tools for the solar and space weather community, and then widely disseminate them online through the SolarSoft software distribution library. Since this work will be performed at the Center for Solar-Terrestrial Research at the New Jersey Institute of Technology (NJIT), the activity will advance discovery and understanding while promoting teaching, training, and learning. The PI plans to integrate the analysis tools developed here into graduate courses at NJIT, including curricula in radio astronomy, solar physics, and plasma physics. This research will also broadly be applicable beyond solar physics, given that both magnetic fields and plasma particle distributions are fundamentally important in astrophysics studies.