相关论文: Solar Physics and the Solar-Stellar Connection at …
The magnetic cycle of the Sun, as manifested in the cyclic appearance of sunspots, significantly influences our space environment and space-based technologies by generating what is now termed as space weather. Long-term variation in the…
We present the scientific case for a future space-based telescope aimed at very high spatial and temporal resolution imaging of the solar photosphere and chromosphere. Previous missions (e.g., HINODE, SUNRISE) have demonstrated the power of…
The abrupt and permanent changes of photospheric magnetic field in the localized regions of active regions during solar flares called magnetic imprints (MIs), have been observed for the past nearly three decades. The well known "coronal…
We take advantage of the HMI/SDO instrument to study the naked emergence of active regions from the first imprints of the magnetic field on the solar surface. To this end, we followed the first 24 hours in the life of two rather isolated…
The magnetic topology and field line random walk properties of a nanoflare-heated and magnetically confined corona are investigated in the reduced magnetohydrodynamic regime. Field lines originating from current sheets form coherent…
Solar flares and coronal mass ejections (CMEs), especially the larger ones, emanate from active regions (ARs). With the aim to understand the magnetic properties that govern such flares and eruptions, we systematically survey all flare…
Strong solar flares and coronal mass ejections, here defined not only as the bursts of electromagnetic radiation but as the entire process in which magnetic energy is released through magnetic reconnection and plasma instability, emanate…
Young solar-type stars rotate rapidly and many are magnetically active; some undergo magnetic cycles similar to the 22-year solar activity cycle. We conduct simulations of dynamo action in rapidly rotating suns with the 3D MHD anelastic…
We analyze high-cadence vector magnetograms (135~s) and flare-ribbon observations of 37 flares from the Solar Dynamics Observatory to understand the spatial and temporal properties of changes in the photospheric vector magnetic field and…
(abridged) The Sun's magnetic activity has steadily declined during its main-sequence life. While the solar photospheric luminosity was about 30% lower 4.6 Gyr ago when the Sun arrived on the main sequence compared to present-day levels,…
We present a detailed investigation on the evolution of observed net vertical current using a time series of vector magnetograms of the active region (AR) NOAA 11158 obtained from Helioseismic Magnetic Imager. We also discuss the relation…
Data obtained by the GONG and MDI instruments over the last seven years are used to study how solar dynamics -- both rotation and other large scale flows -- have changed with time. In addition to the well known phenomenon of bands of faster…
Normal modes of oscillation of the Sun are useful probes of the solar interior. In this work, we use the even-order splitting coefficients to study the evolution of magnetic fields in the convection zone over solar cycle 23, assuming that…
Variations of the weak magnetic fields of the photosphere with periods of the order of the solar magnetic cycle were investigated. Synoptic maps of the photospheric magnetic field produced by NSO Kitt Peak for the period from 1978 to 2016…
In this work, we have studied the temporal evolution of some properties of a sample of superactive regions with the aim to single out the most significant for flare activity forecasting. We have investigated properties of 14 superactive…
A statistical study has been carried out of the relationship between plasma flow Doppler velocities and magnetic field parameters during the emergence of active regions at the solar photospheric level with data acquired by the Michelson…
Planets orbiting young, solar-type stars are embedded in a more energetic environment than that of the solar neighbourhood. They experience harsher conditions due to enhanced stellar magnetic activity and wind shaping the secular evolution…
The solar cycle is a complex phenomenon. To comprehensively understand it, we have to study various tracers. The most important component of this complex is the solar dynamo, which is understood as self-excitation of the solar magnetic…
Magnetic active regions on the Sun are harbingers of space weather events. Understanding the physics of how they form and evolve will improve space weather forecasting. Our aim is to characterise the surface magnetic field and flows for a…
We review recent insights into the dynamics of the solar convection zone obtained from global numerical simulations, focusing on two recent developments in particular. The first is quasi-cyclic magnetic activity in a long-duration dynamo…