The quiet Sun (the 99%, or more, of the solar surface not covered by sunspots or active regions) is receiving increased attention in recent years; its role on the global magnetism and its complexity are being increasingly recognised. A picture of a rather stochastic quiet Sun magnetism is emerging . From these recent works, the quiet Sun magnetism is presented as a myriad of magnetic field vectors having an isotropical distribution with a cascade of scales down to the mean free path of the photon (1 marcsec, or 10km on the solar surface). But this chaotic representation also shows clear signs of intermittency: at a low frequency rate (0.022 events h-1 arcsec-2) the magnetic field appear in the quiet Sun forming well-organised loop structures at granular scales. Right figure shows an example of such small-scale loop (1 arcsec, or 1000 km on the solar surface). We cas see as it is formed by a myriad of nested field lines forming a spartial (and temporal) coherent structure. More interesting, these loops rise to higher layers (see left figure) and their energy input into the chromosphere can be important for the heating of this layer.
Advertised on
References
(2010)The Astrophysical Journal Letters, Volume 714, Issue 2, pp. L94-97
It may interest you
-
The standard cosmological model states that massive galaxies contain a large fraction of dark matter. Dark matter is a transparent substance that does not interact through regular baryonic matter and is only detected through its gravitational pull over the stars and the gas. NGC 1277 is known as the prototype of a relic galaxy, that is, a galaxy that has not accreted other galaxies since it formed. Relic galaxies are extremely rare and are the untouched remains of the giant galaxies that populated the early Universe. Since relic galaxies are very important to understand the conditions in theAdvertised on
-
The transient Swift J1727.8-162 is the latest member of the X-ray binary black hole family to be discovered. They are formed by a black hole and a low-mass star whose gas is stripped off and accreted to the black hole via an accretion disc. The high temperature of the accretion disc makes it shine in all energy bands up to X-rays, and is particularly bright during epochs known as outbursts. In this novel study, published just a few months after the discovery of the system, we present 20 epochs of optical spectroscopy obtained with the GTC-10.4m telescope. The spectra cover the main accretionAdvertised on
-
Accretion disks around compact objects are expected to enter an unstable phase at high luminosity. One instability may occur when the radiation pressure generated by accretion modifies the disk viscosity, resulting in the cyclic depletion and refilling of the inner disk on short timescales. Such a scenario, however, has only been quantitatively verified for a single stellar-mass black hole. Although there are hints of these cycles in a few isolated cases, their apparent absence in the variable emission of most bright accreting neutron stars and black holes has been a continuing puzzle. HereAdvertised on