Abstract
The process of magnetic flux emergence is closely linked to the formation of solar active regions, which are the main sites for most solar eruptions. The Sun’s lower atmosphere and a part of its upper convection zone are partially ionized. In this thesis, we modified the one-fluid magnetohydrodynamic equations to include the effects of partial ionization. Our work involves comparing two simulation scenarios: one with a fully ionized plasma (FI) and the other with a partially ionized plasma (PI). We analyzed and compared these scenarios in both an unmagnetized solar atmosphere and a magnetized solar atmosphere.Our analysis shows that in the PI case, less dense plasma rises more easily to the photospheric layer than in the FI case. The PI plasma changes the structure of the emerging magnetic field, shaping bipolar regions differently and causing the magnetic field to expand upwards sooner. We have found that partial ionization reduces cooling during adiabatic expansion but does not heat the atmospheric plasma. In our 3D experiments, we have found that PI does not prevent coronal unstable magnetic structures from erupting into the outer solar atmosphere. The failed emergence of the flux tube axis in the PI case created differences in the dynamical evolution of the magnetic field in the solar atmosphere compared to the FI case. We also observed differences in temperature, density, and vertical velocity profiles during eruptions, highlighting the impact of partial ionization in the lower atmosphere and upper convection zone.
Comparing PI and FI simulations in a magnetized corona, we found that the first reconnection jet is a multithermal jet and is slower, cooler, and less dense in PI than in FI. For inverted-Y-shaped standard jet we find that the PI jet is less hot, less dense, but faster than the FI jet. We have found the presence of mini-filament-structures in both simulations. We have found that PI have more energetic blowout jets. To conclude this PhD thesis provided new results and shed light on the effects of the partially ionized plasma on magnetic flux emergence and solar eruptive events.
Date of Award | 3 Jul 2025 |
---|---|
Original language | English |
Awarding Institution |
|
Supervisor | Vasileios Archontis (Supervisor) |
Keywords
- Magnetic flux emergence
- Partial ionization
- Heliophysics
- Solar eruptions
- Solar jets
- MHD simulations
Access Status
- Full text open