Description
Solar cycle 25, which is already progressing and is currently moving towards the solar maxima, is characterized by increased solar activity and highly disturbed interplanetary conditions. As a result extreme space weather events are recorded. For example the unusual Forbush Decrease on March 2024, the strongest geomagnetic storm G5 in over two decades on May 2024, and finally the new Ground Level Enhancement events, GLE74, GLE75 and GLE 76 on May, June and November 2024 respectively were recorded.
Neutron monitors (NMs) have been continuously measuring the secondary nucleonic component of the galactic cosmic ray (CR) intensity for more than 70 years. NMs have played a fundamental role in our understanding of: solar modulation, namely significant global and temporal variations in the galactic CR intensity and energy spectra as a function of position inside the heliosphere on long time...
During 2024, three ground level enhancements (GLEs) were observed, with onsets on 11 May, 8 June, and 21 November. GOES-16 and -18 made observations during all three GLEs, and additionally GOES-19 (launched 7 July 2024) made observations during GLE 76. Each satellite carries three solar energetic particle (SEP) instruments: two Solar and Galactic Proton Sensors (SGPS), looking eastward and...
Forbush decrease (or, in more wide sense, Forbush effect) - it is a storm in cosmic rays, which is a part of heliospheric storm and is very often observed simultaneously with a geomagnetic storm. All these three kinds of perturbations: disturbances in the solar wind, magnetosphere and cosmic rays are closely interrelated and caused by the same active processes on the Sun. In the report, they...
The surprising increase in solar activity in 2024, following a relatively tranquil 24th cycle, suggests that we are approaching the solar maximum of the 25th cycle. The complex interplay between disturbed interplanetary and geomagnetic fields affects the cosmic rays reaching the Earth’s surface in various ways.
Positioning the particle spectrometers at elevated altitudes, which analyze the...
Ground-level enhancements (GLEs) represent the highest-energy end of solar energetic particle (SEP) events, forming a distinct class where ions are accelerated to relativistic speeds. This leads to a sudden, significant increase in cosmic rays detected by ground-based instruments, primarily neutron monitors (NMs). This work focuses on GLE74, which occurred on May 11, 2024. Proton observations...
Some solar energetic particle (SEP) events can be registered by ground-based neutron monitors (NMs) measuring the variability of cosmic rays. Those events are called Ground-Level Enhancements (GLEs) and are seen as rapid increases in NM count rates over the background of galactic cosmic rays. GLEs are rare, but the year 2024 was rich for three of them. We report the second GLE of the year that...
A Ground-Level Enhancement (GLE) was detected on May 11, 2024, following a significant Forbush decrease. Simultaneously, a powerful Solar Energetic Particle (SEP) event was measured at the Lagrange L1 point and by the Solar-Terrestrial Relations Observatory Ahead (STEREO-A). This event was triggered by an X5.8 flare and a fast Coronal Mass Ejection (CME) with a speed >1500 km/s which generated...
A series of intense solar flares occurred in May 2024. Among other effects, a remarkable Forbush decrease in the cosmic ray flux was observed on the Earth. This event was observed by neutron and muon detectors installed at the Svalbard, in a high latitude site, characterized by a weak geomagnetic shielding. For this analysis we employed at Ny-Alesund three scintillator-based muon telescopes of...
