Neutron Monitors (NM) have been in continuous operation in a global network since the International Geophysical Year (IGY) 1957/58. Their main purpose is the ground-based observation of temporal fluctuations in the low GeV part of the energy spectrum of cosmic ray particles hitting the Earth's atmosphere. The focus in the use of NM data has however significantly changed over time, from...
The Neutron Monitor DataBase (NMDB) has been created as an EU FP7 project in 2008. Since then, NMDB has grown from 12 participating institutes with 15 stations to more than 50 stations, about half of them currently provide data in real-time. While we created NMDB for the use of Cosmic Ray researchers, the data has been quickly found by and is nowadays being used in many different fields of...
Ground-level enhancements (GLE) designate eventS where relativistic protons and ions of solar origin trigger a cascade of secondary nucleons in the Earth’s atmosphere that can be detected on ground. GLEs require primary particles with energies of at least 430 MeV/nucleon, with a spectrum that may extend to several tens of GeV. They are extremes of solar particle acceleration, which pose...
We investigate the shape and extend of the solar wind transition surfaces, namely the slow (sonic), the fast magnetosonic and the Alven surface, as a function of heliospheric latitude using actual experimental data from Ulysses, Parker Solar Probe and Solar Orbiter pole to pole journey. We also derive the temporal variation of the radius of these surfaces using measurements from spacecraft at...
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...
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...
In our lecture we will look at the history and present of cosmic ray research by the staff of the Institute of Experimental Physics SAS at the Lomnickom Peak site. We will summarize the history of the site and measurements, the results of our work and future perspectives. You will learn, for example, about how the cosmic ray observations with different instruments since 1957 and what...
Various European projects that provide space weather services, such as spacecraft operations and aviation, rely on neutron monitor data. In this presentation, two major European projects will be discussed, respectively ESA Space Safety Program (S2P) Space WEather Service NETwork (SWESNET, https://swe.ssa.esa.int/) and Pan-European Consortium for Aviation Space weather User Services (PECASUS,...
Three years after GLE 73 (October 28, 2021), three distinct GLEs took place before the end of 2024.The first event, GLE 74 registered on May 11, 2024, followed by GLE75 on June, 8 and GLE 76 on November 21. Each event exhibited unique characteristics in terms of intensity, temporal evolution, and spectral properties. Notably,GLE 74 occurred during an irregular Forbush Decrease with sharp...
The availability of high time resolution NM data in near real-time through NMDB makes it possible to generate GLE alerts. Potential stakeholders are researchers in the field of space weather as well as e.g. airlines who have to assess the radiation dose exposure of crew members and passengers along the flight routes. Currently, at least two institutions operate such alert applications. These...
Neutron monitors (NMs) play a crucial role in studying cosmic-ray interactions and atmospheric neutron cascades. However, their response to high-energy neutrons (above 20 MeV) remains uncertain due to the limited availability of neutron cross-section data in simulation frameworks such as GEANT4. This study aims to evaluate the energy sensitivity of a neutron monitor using Monte Carlo...
Temporary decreases in the GCR flux due to the passage of an ICME can be observed in ground-based neutron monitors (NMs) and muon detectors. The details of these Forbush decreases are useful for space weather studies and alerts. We derive hourly variations in the GCR rigidity spectrum during several Forbush decreases using a global fit to count rates from the NM and muon-detector networks, and...
The High Efficiency Neutron Spectrometry Array (HENSA) project develops advanced neutron spectrometers for underground laboratories and cosmic-ray studies. Utilizing a modified Bonner Spheres System (BSS), HENSA achieves ten times higher efficiency than BSS, detecting neutrons from thermal energies to 10 GeV. This enables real-time spectral analysis of solar events such as Ground Level...
We investigate the transport of solar energetic particles (SEPs) during the 28 October 2021 (GLE73) event, focusing on their longitudinal spread. Multi-spacecraft observations revealed a remarkably wide longitudinal diffusion, enabling particles to reach very high energies. In this work, we incorporate SEP measurements from STEREO A, SolO/HET & SEPT, and SOHO/EPHIN, as well as newly available...
Cosmic rays below a few hundred GeV and solar energetic particles are key to understanding how the Sun is interacting with its own solar system, as they respond to the magnetic field that fills the entire Heliosphere, not only during quiet times, but also during episodes of solar activity, as they change the propagation conditions of cosmic rays and solar energetic particles through the...
Two neutron monitors, an 18-IGY since 1958 and a 3-NM64 since 1986, are in operation at the High Altitude Research Station Jungfraujoch in Switzerland. Both neutron monitors are located close to each other but with a difference in altitude of about 100 m (IGY: 3570 m asl, NM64: 3475 m asl). Due to their locations in a high alpine environment, the two neutron monitors are exposed to high...
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...
miniTRASGO is a compact and cost-effective detector for secondary charged cosmic rays, designed for research in solar activity, cosmic ray modulation, and atmospheric physics. Utilizing Resistive Plate Chambers (RPCs), it ensures stable detection rates and high sensitivity, as demonstrated by the observation of Forbush Decreases in March and May 2024 at the Madrid station...
Sun's radiospectroscopy, at different wavelengths, provides information on many phenomena, which extend through the interplanetary medium upto Earth.The ARTEMIS solar radiospectrograph records the dynamic spectrum of solar radio bursts on a daily basis.It is located at the Satellite Communication Center station(SCC)of COSMOTE at Thermopylae,Greece.
The HERON LAB has undertaken its upgrade and...
The recent deployment of two new neutron monitors, HLEA and THIMON, at the summit of Haleakalā, Hawaii, represents a significant advancement in the global neutron monitor network. Positioned at 3,055 meters above sea level, these monitors benefit from reduced atmospheric interference, providing high-quality measurements of galactic cosmic rays (GCRs) and solar neutrons. Operational since...
Open-access data is vital for advancing solar and space physics, promoting collaboration and combination of diverse datasets. To this end, the ARTEMIS-IV/JLS free-access database (ARTDB), presented by the ARTEMIS-IV/JLS Group, provides extensive solar radio observations from the ARTEMIS-IV Multichannel Radiospectrograph, operated by the University of Athens at Thermopylae, Greece (Lat: 38°...
The International Axion Observatory (IAXO) is a planned gaseous detector helioscope designed to detect axions, theorised to be dark matter candidates. A baseline detector prototype, IAXO-D0, is at present undergoing tests in Zaragoza. This prototype is sensitive to background high-energy neutrons that could induce false positive axion detections.
A neutron monitor has been proposed as a way...
I will be presenting the Nest tool (nest.nmdb.eu), dedicated to the representation of the data stored in the NMDB database. Nest has been around for a long time and has evolved over time with new features. As the latest changes to the historic web site are cosmetic in nature, I'd like to take a closer look, in the form of a live demonstration, at the pages that have been developed recently and...
We examine the energy spectra of secondary particles linked to solar events to identify and classify Forbush decreases (FD), ground-level enhancements (GLE), and magnetospheric effects (ME) detected by particle detector networks on Earth's surface.
We present energy spectra of neutrons related to the magnetospheric effect observed on November 5, 2023, and the GLE on May 11, 2024.
We refine...
Hydrological monitoring using cosmic ray neutrons is strongly dependent on heliospheric and geomagnetic conditions. To correct for changes in the heliosphere, the most common approach is to use neutron monitor data. Multiple neutron monitor-based correction methods have been proposed. The derivation, inherent assumptions, and limitations of these methods were examined and a novel method...
Precursors (pre – decreases/pre – increases of the cosmic ray intensity) are observed preceding Forbush decreases. The Cosmic Ray Groups of NKUA and IZMIRAN have studied large Forbush decreases (magnitude > 5%) accompanied by geomagnetic storms (i.e., Dst < -100 nT and 5 ≤ Kp-index ≤ 9) regarding precursors. The threshold value of the equatorial anisotropy one hour before the onset of the...
This study presents a statistical analysis of various properties of all recorded until now Ground Level Enhancement (GLE) events, focusing on their association with solar sources. Specifically, we examine the time difference between the onset of the solar flare and the onset of GLE events as well as the correlation between GLE occurrence and amplitude with the main solar flare...
We have studied the sympathetic flares detected by the GOES satellites during the solar period 1975–2017 (i.e., solar cycles 21–24). We found 2204 sympathetic solar flares out of all 77604. The frequency of the occurrence of sympathetic flares depends on the solar cycle activity. The number of sympathetic solar flares increases with the increase in solar activity and decreases as solar...
The variations in cosmic-ray intensity, measured by ground-based detectors at various latitudes, longitudes, and altitudes, are associated with disturbances in the interplanetary magnetic field near Earth. When these variations interact with the magnetosphere, they cause worldwide Forbush decreases (FD), followed by a gradual recovery. The extent of the flux depletion depends on the type and...
