Space Weather Risks for Space Operations and How These Risks Will Be Addressed in the ESA SSA Programme

The National Oceanic and Atmospheric Administration's Space Environment Center (SEC) is the principal U.S. governmental agency for providing space weather data, information, and forecasts across the user spectrum, including industry, other government entities, and the public. A major change in the reporting structure of the center is poised to occur later this year when Congress approves the fiscal year 2005 budget proposed by the Bush administration. The activities of the SEC, together with its proposed budget, will move from under NOAA's research budget and administration to that of the National Weather Service (NWS), which is also administered by NOAA. The weather service will receive augmented funding to accommodate the SEC as one of the service's National Centers for Environmental Prediction. The move, however, is more than a mere change in the wiring diagram for NOAA's administration. It would appear that NOAA is becoming more serious in recognizing and appreciating the essential responsibility that it, through the SEC, holds for supporting the nation's space environment needs. Indeed, the wording in the NWS portion of the NOAA budget strongly acknowledges this, requesting that Congress “allow the NWS to maintain the SEC's critical forecasts and products in support of the Nation's energy and telecommunications industries, NASA, and the [U.S. Department of Defense].” The SEC has long had, as a part of its mission, a research component. This activity allows the center to maintain an awareness of, and contribute to, advances in solar-terrestrial research, especially as applied to space weather. The NOAA budget for FY2005 suggests that this will continue as the SEC comes under the NWS umbrella, stating that the center “will continue to support the research framework necessary to ensure that new research findings are utilized.” We hope this will continue to be the case over the long term. In addition, the National Weather Service has a long history of interacting with private suppliers of weather information and providing value-added products. Such private-public interactions have sparked tensions in the past between the weather service and the atmospheric weather community, similar to concerns now beginning to be felt in the space weather community (see the related article on this topic by Genene Fisher in Space Weather). We hope the experiences encountered, and lessons learned, in the space and atmospheric weather communities will be beneficial to all parties as private-sector space weather services become stronger over time and as the SEC continues to grow in its service to all users. Louis J. Lanzerotti is Editor of Space Weather, a distinguished research professor at the New Jersey Institute of Technology, and a consulting physicist at Lucent Technologies’ Bell Laboratories.

In the interval of 4–10 September 2017, the Sun presented multiple solar flares from active region AR 2673. There were also coronal mass ejections that interacted with the Earth's magnetosphere. This solar activity produced several space weather events. These events were observed with ground‐based instruments of the Mexican Space Weather Service. The Mexican Array RadioTelescope detected highly perturbed solar transits associated with Type I radio emissions from active regions. The Compact Astronomical Low‐frequency, Low‐cost Instrument for Spectroscopy in Transportable Observatories‐Mexican Array RadioTelescope station detected several radio bursts including a Type III associated with the X8.2 flare on 10 September. The magnetometer detected variations reaching a regional K index of 8.3 during the geomagnetic storm. The ionosphere over Mexico was disturbed by different space weather phenomena with the dominant effects of the geomagnetic storm. We used total electron content data to study latitudinal and longitudinal ionospheric effects in this interval. The cosmic rays monitor detected a Forbush decrease associated also with the geomagnetic storm. This low‐latitude instrumental network in Mexico allowed estimating the regional response to space weather events. Coincidentally with the space weather events referred above, there were also two other types of natural hazards affecting the country at that moment, the hurricane Katia category 2 in the Gulf of Mexico, and two major earthquakes (7 and 19 September 2018). The conjunction of these natural phenomena were close to creating a worst‐case scenario in terms of civil protection reaction.

To improve the forecasting capability of impactful solar energetic particle (SEP) events, the relation between coronal mass ejections (CMEs) and SEP events needs to be better understood. Here we present a statistical study of SEP occurrences and timescales with respect to the CME source locations and speeds, considering all 257 fast (v CME ≥ 900 km s−1) and wide (angular width ≥60°) CMEs that occurred between 2006 December and 2017 October. We associate them with SEP events at energies above 10 MeV. Examination of the source region of each CME reveals that CMEs more often accompany a SEP event if they originate from the longitude of E20–W100 relative to the observer. However, an SEP event could still be absent if the CME is <2000 km s−1. For the associated CME–SEP pairs, we compute three timescales for each of the SEP events, namely the timescale of the onset (TO), the rise time (TR), and the duration (TD). They are correlated with the longitude of the CME source region relative to the footpoint of the Parker spiral (ΔΦ) and v CME. The TO tends to be short for 60°. This trend is weaker for TR and TD. The SEP timescales are only weakly correlated with v CME. Positive correlations of both TR and TD with v CME are seen in poorly connected (large ) events. Additionally, TO appears to be negatively correlated with v CME for events with small .

Coronal mass ejections (CMEs) are one of the main drivers of strong space weather disturbances. The interaction between CMEs and the Earth’s magnetic field can cause a wide range of phenomena and the magnetic configuration and orientation are key factors in determining the geo-effectiveness of this type of events. Modeling these events accurately is an ongoing challenge, and data-driven simulations are a valuable operational and research tool, widely used by the community.Using the 3D data-driven MagnetoHydroDynamical (MHD) heliospheric solar wind and CME evolution model EUHFORIA (European Heliospheric FORecasting Information Asset), our aim is to model CME events that can impact the Earth. Forthcoming missions, developed by ASI (Italian Space Agency), aims to improve space weather forecasting capabilities, particularly for CMEs, solar energetic particles (SEPs), and other interplanetary disturbances.In particular SEPs events are of huge importance for Space Weather risks. It is well established that particle acceleration at shocks is linked to the turbulence characterizing the environment in which particles are propagating. Consequently, understanding the role of turbulence is of fundamental importance for the propagation, acceleration and characterization of SEP events. To account for these processes, we aim to integrate the effects of both large-scale structures and turbulence in the simulations, either by using 3D EUHFORIA outputs or thorough 2.5 MHD simulation performed with MPI-ArmVAC, thereby enhancing the diagnostic capabilities of virtual spacecraft.As a case study, we analyse the event of 3 November 2021, observed by both ACE and Solar Orbiter (SolO), which were nearly co-located in latitude and longitude, with a radial separation of ~22 million km. Comparing EUHFORIA simulations with in situ data from both spacecraft provides valuable insight into the new mission’s potential performance once operational. This study was carried out within the Space It Up project funded by the Italian Space Agency, ASI, and the Ministry of University and Research, MUR, under Contract Grant Nos. 2024-5-E.0-CUP and I53D24000060005.

Radiation Belt Storm Probes: A New Mission for Space Weather Forecasting

The dosimeter Liulin-MO for measuring the radiation environment on board the ExoMars Trace Gas Orbiter (TGO) is a module in the Fine Resolution Epithermal Neutron Detector (FREND). A number of solar energetic particle (SEP) events were observed in Mars orbit from July 2021 to 2024 during the increasing phase and close to the maximum of the 25th solar cycle activity. The results from the SEPs measurements obtained in 2021-2023 by Liulin-MO have been previously reported. Here we present the Liulin-MO results from the observation of the radiation parameters of the SEP events during January- October 2024. The most powerful SEP event registered up to now in TGO orbit started on 20 May 2024. The maximum dose rate during this SEP event has been 2800 ± 280 µGy h-1 and the maximum particle flux - 383 ± 19 cm-2 s-1. The total event lasted for about 64 hours up to 24 May with a long tail of increased dose rates and fluxes. The total dose from SEPs for the 64 hours of the main phase of the SEP event was 24.7 ± 2.5 mGy. The total dose from SEPs during this event is equal to the dose from the galactic cosmic rays (GCR) received for about 200 days at this phase of solar cycle 25. The total dose from all SEPs during January - September 2024 is 36.6 mGy (in Si), which is approximately equal to the dose received from GCR for the same period. The observations of SEPs in Mars orbit are compared to the observations during the same periods of proton fluxes measured by the GOES satellite in Earth orbit. The results show that some of the SEPs observed in Mars orbit, excluding the biggest SEP events of 20-24 May and 05-07 September, are also seen in the GOES proton fluxes data. SEP events recorded both in Mars and Earth orbits are related to coronal mass ejections (CMEs) observed by the SOHO and STEREO A coronagraphs. The paper shows that responsible for most of the SEP events registered both in the Liulin-MO data and in the GOES proton fluxes data are halo CMEs. The paper also shows that the sources of the three most powerful SEP events in Mars orbit - those of 20 May, 23 July and 05 September - are halo CMEs from the far side of the Sun. Some of these CMEs are associated with major X class far-side flares. Long-term investigations of the GCRs radiation parameters in Mars orbit show that in August 2024 (the last month of our data with no recorded SEP events) the dose rate was 6.5 ± 0.65 µGy h-1 and the particle flux - 1.4 ± 0.07 cm-2 s-1. These values are about 40 % of the corresponding maximal values measured by Liulin-MO during the solar cycle 24 minimum in March 2020. The above results show the importance of long-term measurements (at least during a full solar cycle) of the radiation conditions in Mars vicinity. Such measurements will make it possible to obtain the data necessary for the planning of future manned and robotic missions, as well as for the selection of the best time interval in the solar cycle for a manned flight to the planet.

Chemical composition of solar energetic particle events and their association with ground level enhancement

We assess whether a formula obtained by Richardson et al. (2014, https://doi.org/10.1007/s11207‐014‐0524‐8) relating the peak intensity of 14‐ to 24‐MeV protons in a solar energetic particle (SEP) event at 1 AU to the solar event location and the speed of the associated coronal mass ejection (CME) may be used in a scheme to predict the intensity of an SEP event at any location at this heliocentric distance. Starting with all 334 CMEs in the CCMC/SWRC DONKI database in October 2011 to July 2012, we use the CME speed and direction to predict the proton intensity at Earth and the two Solar Terrestrial Relations Observatory spacecraft using this formula. Since most (∼85%) of these CMEs were not in fact associated with SEP events, many SEP events are predicted that are not actually observed. Such cases may be reduced by considering whether type II or type III radio emissions accompany the CMEs, or by selecting faster, wider CMEs. This method is also applied to predict the SEP intensities associated with ∼1,100 CMEs observed by the Solar and Heliospheric Observatory Large Angle and Spectrometric Coronagraph during 1997–2006 in solar cycle 23. Various skill scores are calculated, which assess different aspects of the skill of the SEP predictions. We conclude that the Richardson et al. (2014) formula has potential as a simple empirical SEP intensity prediction tool.

Hostile space weather is one of the principal threats to modern human technology because of the dependency of our lives on satellites. Solar coronal mass ejections, solar flares, and high‐speed solar wind streams often cause some sequences of damaging disturbances within the Earth's magnetosphere, in the atmosphere, and even on the Earth's surface. The time‐varying Sun, as the main source of space weather causes geomagnetic storms and substorms in many ways with coronal mass ejections (CME) being possibly the most harmful among them. CMEs cause transient magnetized plasma flows as interplanetary consequences, which drive the geomagnetic storms and substorms in the Earth's magnetosphere. It is shown that the cyclic solar activity has chaotic characteristics. It seems that the chaotic modeling of solar and geomagnetic activity indices is an important approach for analysis and prediction of the solar extreme events. This is particularly useful for engineers and designers interested in space weather prediction and its applications. One of the most important tools for eliciting the chaotic trends is the “Lyapunov exponents,” which is a useful measure of the stability of a dynamic system. This paper analyzes the variation of Lyapunov exponents (LE) for three solar and geomagnetic activity indices during CMEs: the sunspot number, disturbance storm time, and proton temperature. The analysis has been carried out using the technique of adaptive LE estimation adopted from previous works; the suitable window for which has been determined via trial and error. It is shown that the LE of these solar and geomagnetic activity indices varies rapidly during CMEs. The variation in LEs creates a pattern as a precursor for the forthcoming CME. This precursor, which is an oscillation in the values of Les, begins several steps sooner than the CME's occurrence. Then, during the CME, the LEs decrease to a small positive or a negative value, which demonstrates that during an anomaly such as a CME the chaotic characteristics of solar and geomagnetic activity indices decrease and solar and geomagnetic activity indices follow more regular dynamics.

Space weather forecasting aims at predicting the impacts of the Sun, interplanetary space, and the planetary environment on biological and technological systems. To monitor space weather, the European Space Agency is developing the Vigil mission. Vigil will carry the Plasma Analyser (PLA) instrument. We investigate the expected impact of Solar Energetic Particles (SEPs) on PLA. We analyse previous measurements from Solar Orbiter’s Solar Wind Analyser (SWA) Electron Analyser System (EAS) that, like PLA, uses a microchannel plate (MCP) as its detector. Using a fitting algorithm, we extract the number of erroneous counts created by the interaction between SEPs and the MCP. Using SEP flux measurements from Solar Orbiter’s Energetic Particle Detector (EPD) and multilinear regression, we establish a linear relationship between the number of erroneous counts and SEP fluxes. We define an SEP index, characterizing the impact of SEP events on EAS measurements. We then simulate PLA measurements during SEP events characterized by their SEP index. We show that moderate SEP events cause significant discrepancies in PLA plasma moment estimations under common solar-wind conditions. Based on our results, we propose a correction method for erroneous counts created by SEPs in instruments such as EAS and PLA.

An intense type III radio storm has been disrupted by a fast halo coronal mass ejection (CME) on 2000 April 4. The CME is also associated with a large solar energetic particle (SEP) event. The storm recovers after about10 hrs. We identified another CME that occurs on 2003 November 11 with similar CME properties but there is no type III storm in progress. The 2003 November 11 CME is also not associated with an SEP event above the background (less than 2 pfu), whereas the one with type III storm has an intense SEP event (about 56 pfu). One of the factors affecting the intensity of SEP events is the presence of seed particles that are accelerated by CME-driven shocks. We suggest that the type III storm source, which accelerates electrons to produce the storm, also accelerates ions that serve as seed particles to the CME shock.

Based on the multiple-vantage observations of STEREO, SOHO, wind and other spacecraft, the fast and wide coronal mass ejections (CME) during the 24th solar cycle from January 2010 to September 2014 are selected in this paper. Using the outputs of Richardson’s (2014) empirical model of solar energetic particle (SEP) intensity under different conditions, the effects of its associations such as CME, pre-CME, and type II radio bursts, on SEP intensity are analyzed, and the relationship between SEP event and these characteristics is also discussed. The main conclusions are as follows. 1) The presence or absence of pre-CME within 13 h before fast CME significantly improves the model prediction effect and has a significant influence on whether fast CME produces SEP event. Compared with the events without pre-CMEs, the events with pre-CMEs have a low proportion of false alarms (FR: 47.7% <i>vs.</i> 70%). However, the number of pre-CMEs does not improve the model output. 2) CMEs with type-II radio bursts have significantly lower FR to generate SEP events than fast CMEs without type-II radio bursts (42% <i>vs.</i> 68%). And selecting type-II radio bursts as a constraint will filter out some small/weak SEP events, the relationship between model predictions and observations especially for large SEP events (e.g. <i>I</i><sub>p</sub> ≥ 0.01 pfu/MeV) will stand out. Moreover, if the type-II radio enhancement is taken into account, FR can be further reduced to 29.4%, and the proportion of hits can be further increased (HR: 48.5%), and the model prediction is significantly improved. 3) The larger the start frequency of type II radio bursts, the smaller the end frequency is, and FR decreases slightly, but at the same time, a large number of SEP events are excluded by this condition, and the results show that the constraints on the start/end frequency of type-II radio bursts do not improve the model predictions distinctly. 4) If the sub-classification of type-II radio bursts is considered as the model constraint, the CMEs associated with multi-band type-II radio bursts have better model predictions than those with single-band events. For example, m-DH-km type-II radio bursts have lower FR (35.4%) and higher HR (48%), and the accuracy of empirical model is higher. In summary, we find that in addition to the velocity and angular width of CME, the associations of pre-CME, type II radio bursts and their enhancement, and multi-band sub-classification are the favorable conditions for CME to generate SEP events. The SEP intensities obtained by the empirical model have better consistency with the observations, and better predictions can be obtained. This investigation indicates that SEP events are more likely generated by fast and wide CMEs accompanied by pre-CMEs, multi-band type II radio bursts and their enhancements, which seem to serve as discriminative signal for SEP-rich and SEP-poor CMEs.

Large solar energetic particles (SEPs) can cause adverse space weather hazards to human technology, and such events are especially associated with halo coronal mass ejections (CMEs). But in turn, a significant portion of halo CMEs are not associated with large SEPs. The objective of this study is to gain an understanding of the source region distinctions between halo CMEs in SEP and non-SEP events. Among the 176 halo CMEs observed from 2010 to 2024, we screen out 45 large SEP events and 131 non-SEP events from this data set. It is revealed that CME speed is a good discriminator between SEP and non-SEP events. Through classifying the source regions of all the halo CMEs, we find that 53% of SEP events originate from “single AR (active region),” and 47% from “multiple ARs” or “outside of ARs.” The corresponding proportion for non-SEP events is 70% and 30%. This suggests that SEP source regions are more likely to originate from large-scale sources. We have also calculated the relevant magnetic parameters of the source regions and found that SEP source regions have higher magnetic free energy and reconnection flux compared to non-SEP source regions. However, SEP source regions are smaller in terms of the intensive magnetic parameters such as mean characteristic magnetic twist α and mean shear angles. Our statistical results can provide new potential variables for forecasting SEPs.

Recently we [1] repeated an earlier analysis by [2,3] showing that large (> M3) solar X-ray flares associated with solar energetic particle (SEP) events have significantly lower peak X-ray flux ratios R of 0.04-0.5/0.1-0.8 nm, proxies for flare peak temperatures, than those without SEP events. Since we expect SEP events to be produced by shocks ahead of fast coronal mass ejections (CMEs), this would imply that an X-ray flare of a given peak flux is more likely to have a fast CME and associated SEP event when it has a relatively smaller R. We examine the role played by the ratios R in correlations between X-ray peak flare fluxes and CME speeds Vcme, and then compare CMEs widths W, speeds Vcme, X-ray flare durations ΔT, and R with each other. We resolve the apparent conflict between a global scaling model of eruptive events showing Vcme scaling with higher R and our confirmation that the [2,3] analysis implies faster CMEs are associated with flares of lower R.

Interplanetary coronal mass ejections (ICMEs) are the heliospheric counterparts of solar coronal mass ejections, and their comprehensive cataloging near Earth has enabled significant advances across space science disciplines. As a part of the Project Space Life by Eco Astronomy Inc, this review presents a synthesis of the Near-Earth ICME since 1996” dataset compiled by I. G. Richardson and H. V. Cane, highlighting its historical development, methodology, key findings, and broad applications. The dataset encompasses approximately 600 ICMEs observed at 1 AU from 1996 through early 2024, spanning solar cycles 23, 24, and the rise of 25. We discuss how ICMEs are identified using in-situ plasma, magnetic field, composition, and energetic particle signatures, and how this approach has evolved with improved data (e.g. ACE spacecraft measurements). The ICME catalogs reveals clear solar-cycle trends, ICME occurrence rises by an order of magnitude from solar minimum to maximum with the yearly counts peaking in 2000 (51 events) and dipping to only a few events at recent minima. It also captures intriguing temporal patterns such as a quasi-periodicity of ~150 days in ICME occurrence (Cane & Richardson, January 1, 2003). We synthesize the typical ICME properties (duration, speed, magnetic field strength) and how they vary between cycles: e.g. cycle 23 produced more frequent and faster ICMEs than the weaker cycle 24. The dataset’s extensive annotations (footnotes) link each ICME to associated phenomena like geomagnetic sudden commencements, storm indices, and cosmic ray depressions, allowing analysis of ICME impacts. We review how ~90% of major geomagnetic storms (Dst ≤ –100 nT) in 1996–2005 were caused by ICMEs or their driven shocks (Richardson & Cane, 2007), underlining their geo effectiveness. We summarize statistical correlations between ICME parameters (speed, magnetic field, size) and geomagnetic storm intensity and discuss notable events. Beyond geomagnetism, ICMEs are shown to modulate galactic cosmic rays, causing short-term intensity drops (Forbush decreases) in ~80% of cases (I & H, 2011) and contributing to long-term cosmic-ray modulation over the solar cycle. The rich Richardson-Cane ICME database has fostered multidisciplinary benefits: improving space weather forecasts (by providing empirical event data for CME arrival and storm predictions), informing heliospheric physics (e.g. ICME propagation and solar-cycle variability), elucidating cosmic ray transport (through ICME-caused particle decreases), and aiding studies of impacts on technological systems (satellites, power grids, GPS) and Earth’s atmosphere. We conclude by emphasizing the value of this continually updated ICME catalogs for future research and cross-disciplinary applications, and we include a comprehensive appendix of ICME analysis figures derived from the dataset.