Analysis of Time-Distance Helioseismology for Detection of Emerging Active Regions
| Autor: | John T. Stefan, Andrey M. Stejko, Alexander G. Kosovichev |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Physics
010504 meteorology & atmospheric sciences Phase (waves) Flux FOS: Physical sciences Astronomy and Astrophysics Context (language use) Geodesy 01 natural sciences symbols.namesake Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science QUIET 0103 physical sciences symbols Astrophysics::Solar and Stellar Astrophysics Helioseismology 010303 astronomy & astrophysics Image resolution Doppler effect Noise (radio) Solar and Stellar Astrophysics (astro-ph.SR) 0105 earth and related environmental sciences |
| DOI: | 10.48550/arxiv.2012.01367 |
| Popis: | A time–distance helioseismic technique, similar to the one used by Ilonidis et al., is applied to two independent numerical models of subsurface sound-speed perturbations to determine the spatial resolution and accuracy of phase travel time shift measurements. The technique is also used to examine pre-emergence signatures of several active regions observed by the Michelson Doppler Imager and the Helioseismic Magnetic Imager. In the context of similar measurements of quiet-Sun regions, three of the five studied active regions show strong phase travel time shifts several hours prior to emergence. These results form the basis of a discussion of noise in the derived phase travel time maps and possible criteria to distinguish between true and false-positive detection of emerging flux. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|