Join the disputation
The PhD defence and trial lecture will be 100% in-person. The room opens for participation just before the disputation starts, and closes for new participants approximately 15 minutes after the defence has begun.
Join the trial lecture - 20th of March at 10:15 (Aud. 209, Svein Rosselands Hus)
"Quasi-Periodic Pulsations in Solar and Stellar Flares"
Conferral summary
Soleksplosjoner er plutselige fenomener, hvor enorme mengder energi blir raskt frigjort i form av stråling og akselerering av høy-energiske partikler ved magnetisk omkobling. Avhandlingen analyserer små-skala strukturer forbundet med fotpunktene til soleksplosjoner, og støtter teoretiske modeller som beskriver formasjonen av disse strukturene.
Main research findings:
Solar flares are sudden bursts of energy on the Sun that happen when twisted magnetic fields snap and reconnect. These explosions release huge amounts of magnetic energy into the Sun’s atmosphere and can disrupt Earth’s communications and power systems. Despite their importance, we still do not fully understand how the energy is released and carried down through the atmosphere.
The Swedish 1-meter Solar Telescope (SST) studies the Sun’s lower layers—the photosphere and chromosphere—at very high resolution. Observations from the SST help us see how and where flare energy is deposited, especially in the chromosphere, where bright “flare ribbons” appear.
This thesis examines flare ribbons from five different events using mainly SST data. Each flare differs in strength and position on the Sun, but the ribbons show similar behaviour. Detailed images reveal that ribbons are made of many tiny, short-lived strands. These fine structures are closely spaced, extend vertically, and are often hidden in the cores of chromospheric spectral lines.
The findings support the idea that energy travels from the corona to the chromosphere in a fragmented, patchy way—likely because magnetic reconnection happens in many small, separate sites rather than in a single smooth process.
