Issue |
A&A
Volume 576, April 2015
|
|
---|---|---|
Article Number | A47 | |
Number of page(s) | 6 | |
Section | The Sun | |
DOI | https://doi.org/10.1051/0004-6361/201424624 | |
Published online | 26 March 2015 |
Super-diffusion versus competitive advection: a simulation
1
Dipartimento di FisicaUniversità degli Studi di Roma “Tor
Vergata”,
via della Ricerca Scientifica 1,
00133
Roma,
Italy
e-mail:
delmoro@roma2.infn.it
2
INAF–Istituto di Astrofisica e Planetologia Spaziali, via del
Fosso del Cavaliere 10, 00133
Roma,
Italy
3
Dipartimento di Fisica, Università della Calabria,
Ponte P. Bucci 31/C,
87036
Rende,
Italy
4
CNISM, Unità di Ricerca di Cosenza, Ponte P. Bucci
31/C, 87036
Rende,
Italy
5
Instituto de Astrofísica de Andalucía (CSIC),
Apdo. 3004, 18080
Granada,
Spain
Received: 17 July 2014
Accepted: 22 January 2015
Context. Magnetic element tracking is often used to study the transport and diffusion of the magnetic field on the solar photosphere. From the analysis of the displacement spectrum of these tracers, it has recently been agreed that a regime of super-diffusivity dominates the solar surface. Quite habitually this result is discussed in the framework of fully developed turbulence.
Aims. However, the debate whether the super-diffusivity is generated by a turbulent dispersion process, by the advection due to the convective pattern, or even by another process is still open, as is the question of the amount of diffusivity at the scales relevant to the local dynamo process.
Methods. To understand how such peculiar diffusion in the solar atmosphere takes place, we compared the results from two different data sets (ground-based and space-borne) and developed a simulation of passive tracers advection by the deformation of a Voronoi network.
Results. The displacement spectra of the magnetic elements obtained by the data sets are consistent in retrieving a super-diffusive regime for the solar photosphere, but the simulation also shows a super-diffusive displacement spectrum: its competitive advection process can reproduce the signature of super-diffusion.
Conclusions. Therefore, it is not necessary to hypothesize a totally developed turbulence regime to explain the motion of the magnetic elements on the solar surface.
Key words: convection / hydrodynamics / turbulence / Sun: photosphere
© ESO, 2015
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.