Plasma Composition Variations in Solar Active Regions
The plasma composition of the solar corona is characterised by a varying overabundance of elements with a low first ionization potential (FIP) compared to those with a high FIP – this is called the FIP effect. Typically, the strongest enhancement is observed in active regions, as well as in situ in the slow solar wind. The FIP effect is not observed in the solar photosphere, suggesting that the enhancement of low-FIP elements must take place in the chromosphere. The ponderomotive force model (Laming, 2004) suggests that the FIP effect is driven by Alfvén waves depositing their energy in the chromosphere and, in doing so, applying an upwards ponderomotive force on low-FIP elements which preferentially transports them to the corona. This seminar will focus on discussing how waves with different properties can deposit their energy at varying heights in the chromosphere and affect the plasma composition pattern, i.e. the relative abundance of different elements, observed in the corona. This work highlights the potential for using plasma composition measurement to obtain information about wave activity in the solar atmosphere and estimate the chromospheric height at which wave energy is deposited.
Teodora (Teia) Mihailescu is a postdoctoral researcher at NASA’s Goddard Space Flight Center and USRA, working on spectroscopy and plasma composition using data from Solar Orbiter SPICE and Hinode EIS. She studied BSc Physics at Imperial College London and MSc Space Science and Engineering at University College London (UCL). She completed her PhD in Solar Physics at UCL’s Mullard Space Science Laboratory in 2024. Her PhD work focused on using spectroscopic data from Hinode EIS to characterise plasma composition variations in the Sun’s corona and understand the properties of the drivers responsible for these variations.