Forecast of geomagnetic storms in April–November 2024 based on cosmic ray monitoring results

Since 2013, continuous monitoring of spatial-angular distribution of CRs for each hour of measurements has been carried out at SHICRA SB RAS, using data from the international neutron monitor database NMDB and the method of real-time global survey. For this purpose, nine parameters of the CR distribution are automatically calculated which result from the first two angular moments of the spatial distribution function of particles in interplanetary space. Our earlier studies have shown that before the onset of most geomagnetic storms with the amplitude of the geomagnetic activity Dst index lower than –50 nT there is a sharp increase in amplitudes of north-south components of CR distribution. This can serve as a predictor of the onset of geomagnetic disturbances with a lead time from several hours to 1–2 days. This paper presents the results of forecasting of geomagnetic storms with a Dst amplitude <–50 nT, observed in April–November 2024. It is also shown that the appearance of false predictors is associated with Earth’s entry into large-scale SW disturbances without geomagnetic effects.

A study of the propagation of solar particles in interplanetary space: The center-limb effect of the magnitude of cosmic-ray storms and of geomagnetic storms

Fast Coronal Mass Ejections (CMEs) gather compressed and heated solar wind ahead of them to for turbulent sheath regions. In this presentation we will first demonstrate with recent examples (using e.g. Parker Solar Probe and Solar Orbiter measurements) and the results from a statistical analysis (the ACE spacecraft data) that CME-driven sheath regions can significantly contribute to the acceleration of charged particles in interplanetary space, independent from the effect of the leading shock wave.  Then, we will present the key characteristics of sheath regions, e.g., variations of magnetic fied fluctuation and key turbulent properties across the sheath, that can have the key importance for the particle energization.   

The heliocentric distribution of meteoric particles in interplanetary space is derived, with consideration of the Poynting-Robertson effect, interparticle collision processes and cometary dust injection. Radial distribution functions were derived for zodiacal dust, radar meteors and the meteoroids of mass 10 to the -9th to about 10 to the -10th g (normalized to 1 AU). The number density was found to depend on particle size.

An attempt has been made to derive heliocentric distribution of meteoric particles in interplanetary space. Poynting-Robertson effect, collision process, and cometary dust injection have been included in this study. Three different radial distribution functions for different sizes have been derived. The number density appears to depend on particle size.

Cosmic ray variations due to changes in the magnetosphere are evaluated for severe magnetic storm on 20 November 2003 using data from the worldwide neutron monitor network and the global survey method. From these results the changes in the planetary distribution of magnetic cutoff rigidities during this disturbed period are obtained in dependence of latitude. A correlation between Dst index and cutoff rigidity variations was defined for each cosmic ray station. The maximum changes in cutoff rigidities occurred while Dst index was around −472 nT. Geomagnetic effect in cosmic ray intensity reached at some stations 6–8%, and it seems to be the greatest one over the history of neutron monitor observations. The latitudinal distribution shows a maximum changes at geomagnetic cutoff rigidities around 7–8 GV. This corresponds to unusually low latitudes for maximal effect. Cutoff rigidity variations were also calculated utilizing the last model of Tsyganenko for a disturbed magnetosphere (T01S). A comparison between experimental and modeling results revealed a big discrepancy at cutoff rigidities less than 6 GV. The results on the geomagnetic effect in cosmic rays can be used for validating magnetospheric field models during very severe storms.

Geomagnetic storm is an important subject in space weather forecasting. High speed solar wind originating from coronal holes passes through the interplanetary space about three days before reaching the Earth. It triggers geomagnetic storms which are dominant during the declining phase and the minimum year of a solar cycle. At present, geomagnetic storms forecasting mostly relies on solar wind parameters at 1AU, and geomagnetic storms are predicted in advance only by about 1 hour. In order to predict geomagnetic storms much earlier, it is necessary to establish the quantitative relationship between the characteristic parameters of coronal holes and geomagnetic storms from the point of the Sun, which is the source of high speed solar wind and geomagnetic storm. In this study, 152 coronal holes and relevant geomagnetic storms events from May 2010 to December 2016 are analyzed. Two characteristic parameters of coronal holes are extracted based on SDO/AIA images, and the geomagnetic index <i>ap, Dst</i> and <i>AE</i> during geomagnetic storms are analyzed. The statistical relationship between characteristic parameters of coronal holes and intensity/time of geomagnetic storms is established, which provides a basis for predicting geomagnetic storms in advance by 1~3 days based on solar EUV images.

Vela satellites of orbit r=18 RE measured the intensity of ≲1‐MeV solar protons at two points in the plasma sheet and one in the north tail lobe during an 8‐hour period on April 22, 1971. Intensities were isotropic, except when a sharp gradient was convected past a satellite. Several such gradients have been interpreted as the boundary between plasma sheet and north lobe. Movement of this plasma sheet surface has been observed in coincidence with substorm and geomagnetic storm activity. It is inferred that the region of open field lines at Vela orbit was very small in this event. A prolonged intensity difference by a factor of almost 2 existed across the surface between plasma sheet and lobe for >8 hours, implying very little cross‐field transport of ≲1‐MeV protons. One gradient‐induced anisotropy was anomalous in direction and has been explained by a tongue‐shaped distortion in the surface separating plasma sheet and lobe. A second case of anomalous anisotropy from another event has been explained in a similar way. Intercomparison between Vela and Imp 6, the latter in interplanetary space, suggests the following. Access of ≲1‐MeV solar protons to the north tail lobe was delayed by 3–4 hours, giving an access point 602–872 RE from earth. The intensity there was a little higher than the mean of the interplanetary distribution. The intensity in the dusk plasma sheet lay between the mean in interplanetary space and the integrated intensity of the backward moving interplanetary particles (−1 < µ < 0). The intensity in the dawn plasma sheet was lower and tracked the integrated intensity of the backward moving particles in interplanetary space. This gradient across the plasma sheet at r=18 RE implies that there was not a thorough mixing of ≲1‐MeV protons, at least on a time scale of hours.

Relationship between interplanetary field/plasma parameters with geomagnetic indices and their behavior during intense geomagnetic storms

On a basis of processing of data of measurements of the world-wide neutron monitor network database NMDB by a global survey method in real-time, the behavior of the first two angular moments of cosmic ray distribution function are investigated during the periods of geomagnetic storms that were observed in 2017. It is shown that abrupt increases of positive amplitudes of zonal components, which can be considered as predictors of geomagnetic field disturbances with a probability around 75%, precede geomagnetic storms with Dst <-50 nT. The predictor’s lead time is from a few hours to 1.5 days. A monitoring of geomagnetic disturbances is carried out in real-time mode and results of the forecasting is presented in the Internet through the link http://www.ysn.ru/∼starodub/SpaceWeather/global_survey_real_time.html.

The statistical results concerning the latitude dependence of cosmic-ray storms associated with magnetic storms, analyzed by using the world-wide data of cosmic-ray neutrons obtained at mountain altitudes during the IGY, are presented and discussed. The results obtained without applying the corrections for the storm-time increases in cosmic-ray intensity found by Kondo et al. show that the latitude effect of cosmic-ray storms associated with magnetic storms is strongly dependent on the grade of the magnetic storm. Even after the corrections for the stormtime intensity increases have been applied, the results show that the latitude effect has a close relation with the magnetic storms though the feature somewhat differs from the former results. It is supposed that the latter results are not caused by geomagnetic effect (magnetic storm effect) but by solar modulation effect in interplanetary space. (auth)

This study investigates the ionospheric response over China during the geomagnetic storm that occurred on 1–2 December 2023. The data used include GPS measurements from the Crustal Movement Observation Network of China, BDS-GEO satellite data from IGS MEGX stations, [O]/[N2] ratio information obtained by the TIMED/GUVI, and electron density (Ne) observations from Swarm satellites. The Prophet time series forecasting model is employed to detect ionospheric anomalies. VTEC variations reveal significant daytime increases in GNSS stations such as GAMG, URUM, and CMUM after the onset of the geomagnetic storm on 1 December, indicating a dayside positive ionospheric response primarily driven by prompt penetration electric fields (PPEF). In contrast, the stations JFNG and CKSV show negative responses, reflecting regional differences. The [O]/[N2] ratio increased significantly in the southern region between 25°N and 40°N, suggesting that atmospheric gravity waves (AGWs) induced thermospheric compositional changes, which played a crucial role in the ionospheric disturbances. Ne observations from Swarm A and C satellites further confirmed that the intense ionospheric perturbations were consistent with changes in VTEC and [O]/[N2], indicating the medium-scale traveling ionospheric disturbance was driven by atmospheric gravity waves. Precise point positioning (PPP) analysis reveals that ionospheric variations during the geomagnetic storm significantly impact GNSS positioning precision, with various effects across different stations. Station GAMG experienced disturbances in the U direction (vertical positioning error) at the onset of the storm but quickly stabilized; station JFNG showed significant fluctuations in the U direction around 13:00 UT; and station CKSV experienced similar fluctuations during the same period; station CMUM suffered minor disturbances in the U direction; while station URUM maintained relatively stable positioning throughout the storm, corresponding to steady VTEC variations. These findings demonstrate the substantial impact of ionospheric disturbances on GNSS positioning accuracy in southern and central China during the geomagnetic storm. This study reveals the complex and dynamic processes of ionospheric disturbances over China during the 1–2 December 2023 storm, highlighting the importance of ionospheric monitoring and high-precision positioning corrections during geomagnetic storms. The results provide scientific implications for improving GNSS positioning stability in mid- and low-latitude regions.

\n We propose a model for the acceleration of charged particles in\n interplanetary space that appear during quiet time periods, that is,\n not associated with solar activity events like intense flares or\n coronal mass ejections. The interaction\n of charged particles with modeled turbulent electromagnetic fields,\n which mimic the fields observed in the interplanetary medium,\n is studied.\n The turbulence is modeled by means of a dynamical system,\n the Gledzer-Ohkitani-Yamada (GOY) shell model,\n which describes the gross features\n of the Navier-Stokes equations. The GOY model is used to build\n a 3D velocity field, which in turn is used to numerically solve the\n ideal magneto-hydrodynamic (MHD) induction equation,\n while the electric field is calculated from the ideal Ohm's law.\n Particle acceleration in such an environment is investigated by\n test particle simulations, and the resulting energy distributions\n are discussed and compared to observations of suprathermal electrons\n and ions during quiet periods in interplanetary space.\n \n \n

Introducing adaptive neurofuzzy modeling with online learning method for prediction of time-varying solar and geomagnetic activity indices

The geomagnetic disturbances, mainly geomagnetic storms (GMSs), but also low frequency resonances, touch some people susceptible to cerebrovascular diseases (CVDs). Sometimes the geomagnetic effect is overestimating speculatively. Against this concept we compare the changes of geomagnetic indexes (GMIs) with the changes of additional mortality rate (AMR). We compare by means of cross-correlation functions (CCFs) and use the Wolf number (WN) as referent time scale. We suspect that strong GMSs, like these in 2003, increase the relative common MR 3–4 years later with up to 4×10-5. Otherwise, the typical GMS linked AMR seems to be less than 10-5. Even if these values are overestimated, generally they are small. Analyzing data about Bulgaria and 5 its regions for the last solar cycles, we confirm that the lag of the maxima of the GMS linked ANR behind the WN maxima is ~5 years. We confirm also that the lag of the GMSs maxima behind the WN maximum is 1–2 years. Especially, we found that the lag of the maxima of the CVD linked AMR behind the maxima of the GMSs is 3–4 years. So, we consider the 5 years lag of the AMR linked to the GMSs behind the WN maximum appears a sum of two above mentioned delays, 1–2 years and 3–4 years. In principle, the typical duration of CVDs may be derived if the beginnings are known. In the medicine they are usually unknown. However, suspecting the GMSs as triggers of a part of the CWD linked AMR, we should suppose that these CWDs finish with lethal outcome after 3–4 years.