Disputas: Henrik Eklund
Ph.d.-kandidat Henrik Eklund ved Institutt for teoretisk astrofysikk, Det matematisk-naturvitenskapelige fakultet, vil forsvare avhandlingen “Investigating dynamic small-scale events in the Sun with the Atacama Large Millimeter/sub-millimeter Array” for graden Philosophiae Doctor.
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"Life in Icy Worlds? Prospects of the JUICE mission"
Videoopptaket av prøveforelesningen vil være tilgjengelig her fra 20.09.21 - 22.09.21
Studies of the Sun in the radio regime using highly temporally and spatially resolved interferometric observations of the Sun with the Atacama Large Millimeter/sub-millimeter Array have been performed.
With a combination of the novel solar observations and state-of-the-art numerical simulations, the small-scale dynamics in the solar atmosphere has been studied, which provides further understanding of the dynamic nature of the Sun.
The Sun is dynamic and influences the surrounding planetary system which becomes increasingly imperative to be able to predict as we increase the technology and space exploration. To this end, it is important to understand the transport of energy and the dynamical processes that take place in the solar atmosphere. Radiation at millimeter wavelengths which mainly forms in the mid-layers of the solar atmosphere, the Chromosphere, is a powerful indicator of the temperature of the plasma.
To achieve high sensitivity and resolution, interferometric observations are performed with the Atacama Large Millimeter/sub-millimeter Array (ALMA), which consist of about 66 radio antennas. Many challenges come with interferometric observations of the Sun and the data needs to be carefully handled to reconstruct reliable high frame-rate time-series of images. In the observations, several hundred small-scale dynamic brightening events are detected and their evolution is tracked through time. The origin and physical properties of the brightening events are determined by comparison of their characteristics to state-of-the-art three-dimensional numerical simulations. The accurate temperature measurements of the brightening events provides one step further to understanding the energy transport in the solar atmosphere.