Diagnostic functions of solar coronal magnetic fields from radio observations

Abstract

In solar physics, it is a big challenge to measure the magnetic fields directly from observations in the upper solar atmosphere, including the chromosphere and corona. Radio observations are regarded as the most feasible approach to diagnose the magnetic field in solar chromosphere and corona. However, because of the complexity and diversity of the emission mechanisms, the previous studies have only presented the implicit diagnostic functions of the magnetic field for specific mechanism from solar radio observations. This work collected and sorted out all methods for diagnosing coronal magnetic field from solar radio observations, which are expressed as a set of explicit diagnostic functions. In particular, this work supplemented some important diagnostic methods missed in other reviews. This set of diagnostic functions can completely cover all regions of the solar chromosphere and corona, including the quiet region, active region and flaring source regions. At the same time, it also includes incoherent radiation such as bremsstrahlung emission of thermal plasma above the quiet region, cyclotron and gyro-synchrotron emissions of magnetized hot plasma and mildly relativistic nonthermal electrons above the active regions, as well as coherently plasma emission around flaring source regions. Using this set of diagnostic functions and the related broadband spectral solar radio imaging observations, we can derive the magnetic fields of almost all regions in the solar atmosphere,which may help us to make full use of the spectral imaging observations of the new generation solar radio telescopes (such as MUSER, EVOSA and the future FASR, etc.) to study the solar activities, and provide a reliable basis for the prediction of disastrous space weather events.

19 pages, accepted by RAA

References in corpus (15)

• A Review of Solar Type III Radio Bursts
• Quiet Sun internetwork magnetic fields from the inversion of Hinode measurements
• The Magnetic Field in the Solar Atmosphere
• Global maps of the magnetic field in the solar corona
• Nonlinear force-free modeling of the solar coronal magnetic field
• Measurement of magnetic field and relativistic electrons along a solar flare current sheet
• A large-scale search for evidence of quasi-periodic pulsations in solar flares
• Microwave Quasi-periodic Pulsations in Multi-timescales Associated with a Solar Flare/CME Event
• Observational Test of Coronal Magnetic Field Models I. Comparison with Potential Field Model
• Diagnostics of Coronal Magnetic Fields Through the Hanle Effect in UV and IR Lines
• Coronal Magnetography of a Simulated Solar Active Region from Microwave Imaging Spectropolarimetry
• Modeling of the sunspot-associated microwave emission using a new method of DEM inversion
• Coronal Heating Driven by A Magnetic-gradient Pumping Mechanism in Solar Plasmas
• Measurements of the magnetic field strengths at the bases of stellar coronae using the magnetic-field-induced transition theory
• The early evolution of solar flaring plasma loops

Cited by in corpus (4)

• A Statistical Study of Short-period Decayless Oscillations of Coronal Loops in an Active Region
• Application of a magnetic-field-induced transition in Fe X to solar and stellar coronal magnetic field measurements
• A search for thermal gyro-synchrotron emission from hot stellar coronae
• Solar coronal magnetic field measurements using spectral lines available in Hinode/EIS observations: Strong and weak field techniques and temperature diagnostics