English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Aims. We studied the manifestation of decayless oscillations in 3Dsimulations of coronal loops, driven by random motions. Methods. Using thePLUTO code, we ran magnetohydrodynamic (MHD) simulations of a straightgravitationally stratified flux tube, with its footpoints embedded inchromospheric plasma. We consider transverse waves drivers with a horizontallypolarised red noise power-law spectrum. Results. Our broadband drivers lead tothe excitation of standing waves with frequencies equal to the fundamentalstanding kink mode and its harmonics. These standing kink oscillations havenon-decaying amplitudes, and spectra that depend on the characteristics of theloops, with the latter amplifying the resonant frequencies from the drivers. Wethus report for the first time in 3D simulations the manifestation of decaylessoscillations from broadband drivers. The spatial and temporal evolution of ouroscillation spectra reveals the manifestation of a half harmonic, whichexhibits half the frequency of the identified fundamental mode with a similarspatial profile. Our results suggest that this mode is related to the presenceof the transition region in our model and could be interpreted as being theequivalent to the fundamental mode of standing sound waves driven on pipesclosed at one end. Conclusions. The potential existence of this half harmonichas important implications for coronal seismology, since misinterpreting it forthe fundamental mode of the system can lead to false estimations of the averagekink speed profile along oscillating loops. Finally, its detection couldpotentially give us a tool for distinguishing between different excitation anddriving mechanisms of decayless oscillations in observations.

Decayless oscillations in 3D coronal loops excited by a power-law driver