Related papers: Effects of interplanetary shock inclinations on ni…
Long-term geomagnetic activity presented by the aa index has been used to show that the heliospheric magnetic field has more than doubled during the last 100 years. However, serious concern has been raised on the long-term consistency of…
Solar energetic particles (SEPs) in the small "impulsive" events, primarily accelerated during magnetic reconnection in solar jets, have strong enhancements of the abundances of increasingly heavy elements. In contrast, the shock…
Context: Late on 2013 August 19, STEREO-A, STEREO-B, MESSENGER, Mars Odyssey, and the L1 spacecraft, spanning a longitudinal range of 222{\deg} in the ecliptic plane, observed an energetic particle flux increase. The widespread solar…
We present a 2D kinematic model to study the acceleration of solar energetic particles (SEPs) at a shock driven by a coronal mass ejection. The shock is assumed to be spherical about an origin that is offset from the center of the Sun. This…
Experimental results from Tromso HF pumping experiments in the nightside auroral E region are reported. We found intriguing evidence that a modification of the ionosphere-magnetosphere coupling, due to the effects of powerful HF waves…
A central question for understanding interplanetary coronal mass ejection (ICME) physics and improving space weather forecasting is how ICMEs evolve in interplanetary space. We have updated one of the most comprehensive in situ ICME…
The solar eruption on 2012 January 27 resulted in a wide-spread solar energetic particle (SEP) event observed by STEREO A and the near-Earth spacecraft (separated by 108\degree). The event was accompanied by an X-class flare,…
Experimental investigations of the fine plasma structure of interplanetary shocks are extremely difficult to conduct due to their small thickness and high speed relative to the spacecraft. We study the variations in the parameters of…
The recent superstorm of 2024 May 10-11 is the second largest geomagnetic storm in the space age and the only one that has simultaneous interplanetary data (there were no interplanetary data for the 1989 March storm). The May superstorm was…
We investigate the solar origin and heliospheric evolution of an intense geomagnetic storm that occurred on March 23-24, 2023. Despite multiple candidate CMEs observed between March 19-21, a weak CME detected on March 19 at 18:00 UT was…
Interplanetary coronal mass ejections (ICMEs) can reach the Earth's magnetosphere causing magnetic disturbances. It can be measured by satellite and ground-based magnetometers. Data from the ACE satellite and from the geomagnetic field was…
On 2022 September 5, a large solar energetic particle (SEP) event was detected by Parker Solar Probe (PSP) and Solar Orbiter (SolO), at heliocentric distances of 0.07 and 0.71 au, respectively. PSP observed an unusual velocity-dispersion…
With the rise of satellites and mankind's growing dependence on technology, there is an increasing awareness of space weather phenomena related to high-energy particles. Shock waves driven by coronal mass ejections (CMEs) and corotating…
The newly revised sunspot number series allows for placing historical geoeffective storms in the context of several hundred years of solar activity. Using statistical analyses of the Geostationary Operational Environmental Satellites (GOES)…
Interplanetary coronal mass ejections (ICMEs) are the interplanetary manifestations of solar eruptions. The overtaken solar wind forms a sheath of compressed plasma at the front of ICMEs. Magnetic clouds (MCs) are a subset of ICMEs with…
Solar energetic particles (SEPs) in the energy range 10s KeV/nucleon-100s MeV/nucleon originate from Sun. Their high flux near Earth may damage the space borne electronics and generate secondary radiations harmful for the life on Earth and…
We report on a comparison between space weather events that occurred around the two peaks in the sunspot number (SSN) during solar cycle 24. The two SSN peaks occurred in the years 2012 and 2014. Even though SSN was larger during the second…
We demonstrate that global observations of high-energy cosmic rays contribute to understanding unique characteristics of a large-scale magnetic flux rope causing a magnetic storm in August 2018. Following a weak interplanetary shock on 25…
An X1.7 flare at 10:15 UT and a halo CME with a projected speed of 942 km/s erupted from NOAA solar active region 9393 located at N20W19, were observed on 2001 March 29. When the CME reached the Earth, it triggered a super geomagnetic storm…
We show for the first time that different types of suprathermal ion distributions may exist upstream of a single interplanetary shock. ACE and the two ARTEMIS satellites observed a shock on 8 October 2013. The ARTEMIS P1 and P2 spacecraft…