The heliosphere is a giant bubble-shaped region surrounding the sun and its planets. It is created by the interaction between the interstellar medium in our galaxy and the solar wind that results from the continuous expansion of the outermost solar atmosphere. During the past decades, remote-sensing and in situ observations from ground-based telescopes and spacecraft have revealed a wide variety of energetic phenomena throughout the highly dynamic heliosphere. Even though many of these energetic phenomena may appear different, magnetic reconnection is a universal mechanism that drives many of them. Magnetic reconnection is a fundamental physical process that breaks and rejoins field lines in magnetized plasmas. The rearrangement of magnetic topology at the same time also converts magnetic energy into various forms, including plasma bulk kinetic and thermal energy, as well as nonthermal energy of high-energy particles.
Activities associated with magnetic reconnection are plentiful in the lower-layer solar atmosphere, such as microflares, Ellerman bombs, UV bursts, surges, and spicules. In the corona and near-sun region, flares, filament evolutions, coronal mass ejections (CMEs), helmet streamers, and solar energetic particles (SEPs) are all related to magnetic reconnection. In the earth's and other planetary magnetospheres, the impacts from the solar wind, CMEs, and corotating interaction regions (CIRs) lead to magnetic reconnection inside the magnetopause and the magnetotail. In interplanetary space, the large-scale heliospheric current sheet (HCS), magnetic clouds, and turbulence-driven thin current sheets are where magnetic reconnection or reconnection exhaust operates.
The vastly diverse environments and plasma regimes of heliospheric reconnection events pose tremendous challenges to observational and numerical studies. Outstanding open questions such as energy releasing and cascading processes, topology changes, reconnection rate, dissipation scaling laws, formation of magnetic substructures, wave-particle interactions, and particle acceleration in reconnection regions are not only of fundamental scientific interest but also crucial for space weather prediction. To unravel these puzzles in complex plasmas calls for new observational data analysis and numerical simulation techniques. Moreover, significant progress is often achieved when observation and numerical simulation go hand in hand.
This Research Topic is devoted to observation and modeling of magnetic reconnection occurring in different magnetic structures in the heliosphere at all scales. We welcome contributions to this general topic, including, but not limited to, the following areas of particular interest:
1. Observational and numerical studies on magnetic reconnection related to solar activity, solar wind, HCS, SEPs, and magnetospheres;
2. 3D magnetic reconnection in current sheets and quasi-separatrix layers, cascading processes, and internal substructures;
3. Fundamental understandings of turbulent reconnection and fast reconnection;
4. Turbulent properties in the solar atmosphere, solar wind, and magnetospheres;
5. Acceleration and transport of energetic particles;
6. Magnetic reconnection in partially ionized plasmas in the lower solar atmosphere with non-equilibrium ionization and radiative cooling effects.
The heliosphere is a giant bubble-shaped region surrounding the sun and its planets. It is created by the interaction between the interstellar medium in our galaxy and the solar wind that results from the continuous expansion of the outermost solar atmosphere. During the past decades, remote-sensing and in situ observations from ground-based telescopes and spacecraft have revealed a wide variety of energetic phenomena throughout the highly dynamic heliosphere. Even though many of these energetic phenomena may appear different, magnetic reconnection is a universal mechanism that drives many of them. Magnetic reconnection is a fundamental physical process that breaks and rejoins field lines in magnetized plasmas. The rearrangement of magnetic topology at the same time also converts magnetic energy into various forms, including plasma bulk kinetic and thermal energy, as well as nonthermal energy of high-energy particles.
Activities associated with magnetic reconnection are plentiful in the lower-layer solar atmosphere, such as microflares, Ellerman bombs, UV bursts, surges, and spicules. In the corona and near-sun region, flares, filament evolutions, coronal mass ejections (CMEs), helmet streamers, and solar energetic particles (SEPs) are all related to magnetic reconnection. In the earth's and other planetary magnetospheres, the impacts from the solar wind, CMEs, and corotating interaction regions (CIRs) lead to magnetic reconnection inside the magnetopause and the magnetotail. In interplanetary space, the large-scale heliospheric current sheet (HCS), magnetic clouds, and turbulence-driven thin current sheets are where magnetic reconnection or reconnection exhaust operates.
The vastly diverse environments and plasma regimes of heliospheric reconnection events pose tremendous challenges to observational and numerical studies. Outstanding open questions such as energy releasing and cascading processes, topology changes, reconnection rate, dissipation scaling laws, formation of magnetic substructures, wave-particle interactions, and particle acceleration in reconnection regions are not only of fundamental scientific interest but also crucial for space weather prediction. To unravel these puzzles in complex plasmas calls for new observational data analysis and numerical simulation techniques. Moreover, significant progress is often achieved when observation and numerical simulation go hand in hand.
This Research Topic is devoted to observation and modeling of magnetic reconnection occurring in different magnetic structures in the heliosphere at all scales. We welcome contributions to this general topic, including, but not limited to, the following areas of particular interest:
1. Observational and numerical studies on magnetic reconnection related to solar activity, solar wind, HCS, SEPs, and magnetospheres;
2. 3D magnetic reconnection in current sheets and quasi-separatrix layers, cascading processes, and internal substructures;
3. Fundamental understandings of turbulent reconnection and fast reconnection;
4. Turbulent properties in the solar atmosphere, solar wind, and magnetospheres;
5. Acceleration and transport of energetic particles;
6. Magnetic reconnection in partially ionized plasmas in the lower solar atmosphere with non-equilibrium ionization and radiative cooling effects.
