Conveners
Poster Session 5.1
- Etienne Pariat (LESIA, Observatoire de Paris)
It is well established that the total solar irradiance (TSI) varies on
timescales of minute to centuries. On timescales of minutes to hours
the TSI varies due to the globally-averaged superposition of solar
turbulent convection and oscillations, while on solar-cycle and
solar-rotation timescales the majority of the TSI-amplitude
fluctuations are the result of opposing brightenings caused...
The solar photosphere is characterized by the presence of several structures being sunspots the most visible manifestation of the magnetic field immersed in the convective plasma. The study of such active regions in the photosphere includes the analysis of formation, growth and decay of sunspots. These evolutionary processes are directly related to phenomena of solar activity occurring at...
Magnetic field vector observations in the solar photosphere have generally revealed a non-zero value of the divergence: the vertical field component gradient is found on the order of 3 G/km when the horizontal field component gradient is of 0.3 G/km only. This has first to be assigned to the fact that the measured quantity is the magnetic field H, which is related to the divergence-free...
A large-scale magnetic cycle is possible in the Sun and other stars as long as the large-scale shear and helicity of the plasma flow in their convection zones are sufficiently strong. Hence, there is a critical dynamo number for each star for the operation of a large-scale dynamo. As a star spins down, it is expected that the large-scale dynamo ceases to operate above a critical rotation...
The Babcock-Leighton (BL) mechanism, in which the poloidal field is produced by the emergence and subsequent dispersal of sunspot groups, has been received more and more observational evidence during the past decade. Most BL-type dynamo models assume that the toroidal field is generated in the tachocline. However, recently the importance of the tachocline has been questioned by magnetic...
The solar dipole moment at cycle minimum is considered to be the most reliable precursor to determine the amplitude of the subsequent cycle. Numerical simulations of the surface flux transport (SFT) model are widely used to effectively predict the dipole moment. An algebraic method was recently proposed to quickly predict the contribution of an active region (AR) to the axial dipole moment at...
We investigate a new method to obtain the plasma parameters of solar prominences observed in the Mg II h&k spectral lines by comparing line profiles from the IRIS satellite to a bank of profiles computed with a one-dimensional non-LTE radiative transfer code. The prominence observations were carried out by the IRIS satellite on 19th April 2018. Using a grid of 1007 one-dimensional non-LTE...
