Related papers: The solar wind disappearance event of 11 May 1999:…
Understanding the nature and evolution of the photospheric helicity flux transfer is a key to reveal the role of magnetic helicity in coronal dynamics of solar active regions. Using SDO/HMI photospheric vector magnetograms and the derived…
We present a detailed examination of the features of the Active Region (AR) NOAA 10798. This AR generated coronal mass ejections (CMEs) that caused a large geomagnetic storm on 24 August 2005 with the minimum Dst index of -216 nT. We…
Coronal holes (CHs) are widely considered as the main sources of high-speed solar wind streams. We validate this thesis comparing the smoothed time series of solar wind speed measured by Advanced Composition Explorer (ACE) and various…
An interplanetary shock driven by a coronal mass ejection (CME) containing an interval of sub-Alfv\'enic flow impacted Earth on April 23, 2024. In this article, we analyze the turbulence in the sheath region between the shock and CME to…
In the standard model, magnetic reconnection at a vertical current sheet above the flare arcade is key to explaining many aspects of solar eruptions. The supra-arcade region is where the vertical current sheet is supposedly located, and…
The activity of the Sun alternates between a solar minimum and a solar maximum, the former corresponding to a period of "quieter" status of the heliosphere. During solar minimum, it is in principle more straightforward to follow eruptive…
NOAA Active Region (AR) 13664/8 produced the most intense geomagnetic effects since the ``Halloween'' event of 2003. The resulting extreme solar storm is believed to be the consequence of multiple interacting coronal mass ejections (CMEs).…
Aims: We investigate the temporal evolution of magnetic flux emergence in the quiet Sun atmosphere close to disk center. Methods: We combine high-resolution SoHO/MDI magnetograms with TRACE observations taken in the 1216 {\AA} channel in…
Using the data on magnetic field maps and continuum intensity for Solar Cycles 23 and 24, we explored 100 active regions (ARs) that produced M5.0 or stronger flares. We focus on the presence/absence of the emergence of magnetic flux in…
The impact of solar-stellar activity on planetary environments is a topic of great interest within the Sun-Earth system as well as exoplanetary systems. In particular, extreme events such as flares and coronal mass ejections have a profound…
The properties of the solar wind, as measured in situ throughout the heliosphere, depend both on the characteristics of its coronal source and on the intrinsic processes governing its interplanetary evolution. Recently, radial and Parker…
A solar type-I noise storm is produced by accelerated particle beams generated at active regions undergoing magnetic field restructuring. Their intensity varies by orders of magnitude within sub-second and sub-MHz scales. But, the…
We present a case study of the 13 July 2004 solar event, in which disturbances caused by eruption of a filament from an active region embraced a quarter of the visible solar surface. Remarkable are absorption phenomena observed in the…
We investigate the solar phenomena associated with the origin of the solar energetic particle (SEP) event observed on 2013 April 11 by a number of spacecraft distributed in the inner heliosphere over a broad range of heliolongitudes. We use…
The first two orbits of the Parker Solar Probe (PSP) spacecraft have enabled the first in situ measurements of the solar wind down to a heliocentric distance of 0.17 au (or 36 Rs). Here, we present an analysis of this data to study solar…
We present a numerical investigation of the coronal evolution of a coronal mass ejection (CME) on 2005 August 22 using a 3-D thermodynamics magnetohydrodynamic model, the SWMF. The source region of the eruption was anemone active region…
Both coronal holes and active regions are source regions of the solar wind. The distribution of these coronal structures across both space and time is well known, but it is unclear how much each source contributes to the solar wind. In this…
The acceleration of the young solar wind is studied using the first 17 encounters of Parker Solar Probe. We identify wind intervals from different source regions: coronal hole (CH) interiors, streamers, and low Mach number boundary layers…
The Sun is the major source of heat and light in our solar system. The solar cycle is the 11-year cycle of solar activity that can be determined by the rise and fall in the numbers and surface area of sunspots. Solar activity is associated…
How has the solar wind evolved to reach what it is today? In this review, I discuss the long-term evolution of the solar wind, including the evolution of observed properties that are intimately linked to the solar wind: rotation, magnetism…