Kom med til doktorforsvar

Beskrivelse på engelsk:

Clouds and lightning have been known to humankind for millennia, but we still lack details on cloud formation, lightning and associated phenomena. This thesis offers new insights into these atmospheric processes through theoretical work and numerical simulations.

A new computational model is introduced to explore how sulphuric acid molecules cluster to form the seeds of cloud condensation nuclei in Earth’s atmosphere. The findings reveal that stochastic effects play an important role in how these clusters grow. The same model is used to simulate the growth of titanium dioxide (TiO2), clusters as they occur in the atmosphere of exoplanets and brown dwarfs, concluding that larger clusters might be detectable from ground or space giving a hint on the existence of clouds in such atmospheres.

Considering discharge physics, a thorough study on the inception and propagation of lightning inside thunderclouds and Transient Luminous Events above is performed, emphasizing that the relation between the ambient gas and the ambient electric field is crucial for discharge properties. Particularly, it shows that the inception of lightning, which might have been connected to the origin of life on Earth, might have been more difficult in the atmosphere of Primordial Earth than previously thought.

This work also addresses Terrestrial Gamma-Ray Flashes, beams of energetic X- and gamma-rays, constituting one of the most energetic phenomenon on Earth, emitted from thunderstorms. Numerical results show that air perturbations and particularly the large electric fields around and ahead of the lightning channels create a suitable environment for the emission of such energetic radiation, which itself is capable of influencing discharge propagation.

Finally, the thesis introduces innovative ways to share knowledge, including an audiovisual review and a proposed structure for an Atmospheric Electricity course. These tools aim to train the next generation of researchers in cloud physics, lightning, and associated phenomena.

Læs afhandlingen online på orbit.dtu.dk 

Læs mere om dokorforsvar og muligheden for at være uofficiel opponent

Deltag via Zoom: https://dtudk.zoom.us/j/69095347826