Project description

Solar chromosphere is a dynamic interface layer of the Sun's atmosphere located between the photosphere and corona which plays an important role in transporting energy and matter into the outer layers and is crucial for understanding of coronal heating. Full understanding of this layer is still elusive mostly due to the lack of suitable measurements and instruments. The aim of this project is to utilize solar observations with the Atacama Large Millimeter/submillimeter Array (ALMA), a new state-of-the-art and currently the world largest ground-based astronomical facility, capable of observing almost all types of celestial objects including the Sun. The main advantage of ALMA solar observations is mapping of the solar chromosphere with an unprecedented spatial, temporal, and spectral resolution in the wavelength range between 0.3 mm and 8.6 mm. It can also be used as an approximately linear thermometer - the measured brightness temperature is directly proportional to the gas temperature of the observed structure or the continuum-forming layer in the solar atmosphere. Formation height of the continuum radiation increases with increasing wavelength of the observation which, coupled with ALMA's high spectral resolution, enables very accurate measurements of chromosphere's temperature as a function of height. All of these capabilities of ALMA will provide the possibility to investigate full 3D structure of the chromosphere and many interesting dynamic phenomena therein. The main goal of the proposed research is to improve understanding of the solar chromosphere using the new advanced instrument ALMA. 



O1: Analysis of large-scale structures observed by ALMA 
O1.1. Analysis of active regions
O1.2. Analysis of prominences on solar limb
O1.3. Analysis of prominences on solar disc
O1.4. Analysis of large-scale magnetic field
O1.5. Analysis of coronal holes
O1.5. Analysis of polar brightenings

O2: Analysis of small-scale structures observed by ALMA 
O2.1. Anaylsis of ALMA bright points in quiet Sun regions
O2.2. Analysis of ALMA bright points in coronal holes
O2.3. Analysis of small-scale magnetic fields
O2.4. Analysis of sunspot fine structure

O3: Modelling and interpretation of ALMA observations 
O3.1. Investigation of centre to limb brightness function
O3.2. Modelling of various solar structures and comparison with observations

O4: Impact on other fields of solar physics 
O4.1. Cross-correlation of ALMA images to determine solar rotation
O4.2. Determination of solar rotation with tracers and comparison with ALMA results
O4.3. Analysis of eruptive phenomena