Presentation #209.02 in the session Connecting Magnetic Reconnection across Space and Laboratory Plasmas.
Magnetic reconnection is vital for explosive energy release in solar/stellar flares and substorms in the magnetosphere, and is also observed in fusion experiments. In-situ measurements in fusion laboratories and in earth’s magnetosphere provide direct diagnostics of plasma, field, and particle properties at or near the site of reconnection, and remote-sensing, multi-wavelength observations of the solar atmosphere comprehensively capture the global dynamics and energetics, which are manifestations of reconnection energy release. Magnetic field evolution on the global scale is also crucial for the build-up leading to the onset of magnetic reconnection. In the past decade, a suite of space- and ground-based telescopes have observed a large number of reconnection energy release events with unprecedented detail in temporal, spatial, and spectral domains. Limb observations of the corona reveal plasma flows, and sometimes produce plasma and field measurements near the reconnection current sheet, whereas on-disk observations help construct the magnetic topology and provide complementary diagnostics of energy release by reconnection. In spite of this progress, there are substantial challenges to advance the understanding of reconnection physics from observations. We are not able to observe the coupling across the range of scales over which different physics occurs. We lack direct measurements of magnetic field and plasma properties at the scene, particularly prior to the reconnection onset and during the reconnection. Mechanisms for energy conversion and partition are largely unclear, so are predictable observational signatures. The three-dimensional dynamics are widely recognized but difficult to characterize. The final resolution awaits breakthroughs in technical capabilities; on the other hand, cross-field and cross-domain approaches may be explored to help piece together properties and energetics of magnetic reconnection.
Acknowledgment: Drs. Dana Longcope, Paul Cassak, Eric Priest, & SolFER collaboration.