First detection of acoustic-like flux in the middle solar corona

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F25%3A00639436" target="_blank" >RIV/67985815:_____/25:00639436 - isvavai.cz</a>

Výsledek na webu

<a href="https://hdl.handle.net/11104/0369957" target="_blank" >https://hdl.handle.net/11104/0369957</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/202554034" target="_blank" >10.1051/0004-6361/202554034</a>

Jazyk výsledku

angličtina

Název v původním jazyce

First detection of acoustic-like flux in the middle solar corona

Popis výsledku v původním jazyce

Context. Waves are thought to play a significant role in the heating of the solar atmosphere and the acceleration of the wind. Among the many types of waves observed in the Sun, the so-called p modes with a 3 mHz frequency peak dominate the lower atmosphere. In the presence of magnetic fields, these waves can be converted into magnetohydrodynamic modes, which then leak into the corona through magnetic conduits. High-resolution off-limb observations have revealed signatures of ubiquitous and global 3 mHz oscillations in the corona, although they are limited to low heights and to incompressible modes. Aims. We present high-cadence, high-resolution observations of the corona in the range 1.7-3.6 R-circle dot taken in broad-band 580-640 nm visible light by the Metis coronagraph on board Solar Orbiter. These observations were designed to investigate density fluctuations in the middle corona. Methods. The data were acquired over several days in March 2022, October 2022, and for two days in April 2023. We selected representative regions of the corona on three sample dates. Analysis of the data in those regions revealed the presence of periodic density fluctuations. By examining several time-distance diagrams, we determined the main properties (apparent propagation speed, amplitude) of those fluctuations. We also show power spectra in selected locations in order to determine the dominant frequencies. Results. We found wave-like, compressible fluctuations of low amplitude on the order of 0.1% of the background in several large-scale regions in the corona at least up to 2.5 R-circle dot. We also found that the apparent propagation speeds of these perturbations typically fall in the range 150-450 km s(-1). A power spectrum analysis of the time series revealed an excess power in the range 2-7 mHz, often with peaks at 3 or 5 mHz, i.e. in a range consistent with p-mode frequencies of the lower solar atmosphere.

Název v anglickém jazyce

First detection of acoustic-like flux in the middle solar corona

Popis výsledku anglicky

Context. Waves are thought to play a significant role in the heating of the solar atmosphere and the acceleration of the wind. Among the many types of waves observed in the Sun, the so-called p modes with a 3 mHz frequency peak dominate the lower atmosphere. In the presence of magnetic fields, these waves can be converted into magnetohydrodynamic modes, which then leak into the corona through magnetic conduits. High-resolution off-limb observations have revealed signatures of ubiquitous and global 3 mHz oscillations in the corona, although they are limited to low heights and to incompressible modes. Aims. We present high-cadence, high-resolution observations of the corona in the range 1.7-3.6 R-circle dot taken in broad-band 580-640 nm visible light by the Metis coronagraph on board Solar Orbiter. These observations were designed to investigate density fluctuations in the middle corona. Methods. The data were acquired over several days in March 2022, October 2022, and for two days in April 2023. We selected representative regions of the corona on three sample dates. Analysis of the data in those regions revealed the presence of periodic density fluctuations. By examining several time-distance diagrams, we determined the main properties (apparent propagation speed, amplitude) of those fluctuations. We also show power spectra in selected locations in order to determine the dominant frequencies. Results. We found wave-like, compressible fluctuations of low amplitude on the order of 0.1% of the background in several large-scale regions in the corona at least up to 2.5 R-circle dot. We also found that the apparent propagation speeds of these perturbations typically fall in the range 150-450 km s(-1). A power spectrum analysis of the time series revealed an excess power in the range 2-7 mHz, often with peaks at 3 or 5 mHz, i.e. in a range consistent with p-mode frequencies of the lower solar atmosphere.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10308 - Astronomy (including astrophysics,space science)

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2025

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Astronomy & Astrophysics

ISSN

0004-6361

e-ISSN

1432-0746

Svazek periodika

701

Číslo periodika v rámci svazku

Sept.

Stát vydavatele periodika

FR - Francouzská republika

Počet stran výsledku

17

Strana od-do

A199

Kód UT WoS článku

001574075800012

EID výsledku v databázi Scopus

2-s2.0-105016598138