Article
Astronomy & Astrophysics
Nina Dresing, Athanasios Kouloumvakos, Rami Vainio, Alexis Rouillard
Summary: This study investigates the role of CME-driven shocks in accelerating solar energetic electrons. By analyzing observations from the STEREO spacecraft, the study reveals significant correlations between the peak intensities of energetic electrons and the Mach number of the associated shocks. The findings suggest that high-energy electrons are mainly accelerated by the shocks, while low-energy electrons are likely produced through a combination of flare and shock-related acceleration processes.
ASTROPHYSICAL JOURNAL LETTERS
(2022)
Article
Astronomy & Astrophysics
A. Santa Fe Duenas, R. W. Ebert, M. A. Dayeh, M. I. Desai, L. K. Jian, G. Li
Summary: We examined variations in energetic storm particle (ESP) heavy-ion average intensities and energy spectra between 0.1 and 75 MeV nucleon(-1) for coronal mass ejection (CME)-driven interplanetary shocks. Comparing observations from solar cycles 23 and 24, we found that the number of heavy-ion ESP events was higher during cycle 23 and there were more events at higher energies (>10 MeV nucleon(-1)). This suggests more efficient ESP acceleration during cycle 23.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Sumanth Rotti, Berkay Aydin, Manolis K. Georgoulis, Petrus C. Martens
Summary: We present a catalog of solar energetic particle (SEP) events covering solar cycles 22, 23 and 24 and integrate three existing catalogs based on satellite data. The catalog includes 341 SEP events, of which 245 events reach the threshold for significant proton events. Researchers can access time-series data and intensity profiles of proton fluxes for each event, aiding understanding of SEPs and their source eruption characteristics for space weather prediction.
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
(2022)
Article
Environmental Sciences
Janis Balodis, Madara Normand, Inese Varna
Summary: The study analyzed the impact of space weather on Latvian GPS observations, focusing on faults and extreme space weather events. Out of over 36 million position determination solutions examined, a small percentage were found to contain errors, with an extremely low percentage having errors exceeding 50 meters.
Article
Astronomy & Astrophysics
Kosuke Kihara, Ayumi Asai, Seiji Yashiro, Nariaki V. Nitta
Summary: This study investigates two solar energetic particle events with different TO in the western hemisphere, despite similar CME speed and source region longitude. The reasons for the difference in TO, or proton release times, are examined by analyzing CME height-time profiles and radio dynamic spectra. The study also explores how CME-CME interactions and active region properties may affect proton release times.
ASTROPHYSICAL JOURNAL
(2023)
Review
Astronomy & Astrophysics
Nariaki Nitta, Tamitha Mulligan, Emilia K. J. Kilpua, Benjamin J. Lynch, Marilena Mierla, Jennifer O'Kane, Paolo Pagano, Erika Palmerio, Jens Pomoell, Ian R. Richardson, Luciano Rodriguez, Alexis P. Rouillard, Suvadip Sinha, Nandita Srivastava, Dana-Camelia Talpeanu, Stephanie L. Yardley, Andrei N. Zhukov
Summary: Geomagnetic storms, influenced by coronal mass ejections, can be difficult to predict due to the presence of stealth CMEs with elusive solar signatures, potentially caused by observational limitations or weak coronal features.
SPACE SCIENCE REVIEWS
(2021)
Article
Astronomy & Astrophysics
Rositsa Miteva, Susan W. Samwel, Svetoslav Zabunov
Summary: This study presents the first comprehensive analysis of the solar energetic electrons (SEEs) detected by ACE/EPAM satellite and remotely observed radio signatures during solar cycles 23 and 24 (1997-2019). The study identifies the solar origin of the SEEs and calculates the occurrence rates as a function of radio wavelength. The tendencies of different burst appearances with respect to solar cycle, helio-longitude, and SEE intensity are demonstrated, and a comparison with the results using solar energetic protons is discussed.
Article
Astronomy & Astrophysics
Bin Zhuang, Noe Lugaz, Tingyu Gou, Liuguan Ding
Summary: The study revealed that in the scenario of twin coronal mass ejections (CMEs), the speed of the primary CME (priCME) has the highest correlation with the peak intensity of solar energetic particles (SEPs). Furthermore, the combination of CME speed and propagation direction showed a higher correlation with SEP peak intensity. This indicates the dominant role of priCME in controlling SEP enhancements and emphasizes the consideration of latitudinal effects.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
L. Rodriguez-Garcia, L. A. Balmaceda, R. Gomez-Herrero, A. Kouloumvakos, N. Dresing, D. Lario, I. Zouganelis, A. Fedeli, F. Espinosa Lara, I. Cernuda, G. C. Ho, R. F. Wimmer-Schweingruber, J. Rodriguez-Pacheco
Summary: This study aims to identify potential correlations between solar energetic electron (SEE) events measured by the MESSENGER mission and the properties of parent solar activity phenomena. Statistical analysis reveals an asymmetry in the connection angles (CAs) for SEE events with the highest peak intensities, and moderate to strong correlations are found between the electron peak intensity and the maximum speed of CME-driven shock, flare peak intensity, and CME speed at apex for well-connected events. The correlations become blurred when including poorly connected events.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Leon Kocharov, Alexander Mishev, Esa Riihonen, Rami Vainio, Ilya Usoskin
Summary: Major solar eruptions can generate solar particle events that can be detected by neutron monitors worldwide. This study analyzes the similarities between two events with similar time profiles and explores the relationship between the events and their progenitor solar flares and coronal mass ejections. The results suggest that a single solar eruption can contribute to multiple components of solar energetic particles.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Wenlong Liu, Xiangliang Kong, Fan Guo, Lulu Zhao, Shiwei Feng, Feiyu Yu, Zelong Jiang, Yao Chen, Joe Giacalone
Summary: This article conducts a comparative analysis of two ground-level enhancement (GLE) events, focusing on the effects of large-scale magnetic field configuration near active regions on particle acceleration and release. It is found that the locations of solar flares in the two events result in different variations in early-stage solar energetic particle (SEP) intensities and energy spectra. The article suggests that coronal mass ejections (CMEs) and magnetic structures played an important role in the acceleration and release of the highest-energy particles in the two events.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Alessandro Bruno, Ian G. Richardson
Summary: A new empirical model is proposed to predict the intensity spectra of solar energetic particle (SEP) events based on multi-point spacecraft measurements. The model is tested for its performance and shows remarkable agreement with observed results despite its simplicity.
Article
Astronomy & Astrophysics
S. N. A. Syed Zafar, R. Umar, N. H. Sabri, M. H. Jusoh, A. N. Dagang, A. Yoshikawa
Summary: Previous studies have shown that solar activities such as coronal mass ejections and solar flares can lead to the development of storms and high-speed streams. This study investigates the response of the geomagnetic index SYM/H to solar wind parameters, as well as the ground geomagnetic field responses at low-latitude stations. Findings suggest delayed response of the Earth's magnetosphere to weak geomagnetic storms, while strong solar wind and IMF variations can excite the Earth's H-component during geomagnetic storms caused by solar activities.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
A. Kumari, D. E. Morosan, E. K. J. Kilpua, F. Daei
Summary: This study investigates the occurrence of type II solar radio bursts during solar cycles 23 and 24 and their association with coronal mass ejections (CMEs). The results show that the majority of type II bursts are associated with CMEs, but there are also some bursts without a clear CME association. Cycle 24 has more CMEs than cycle 23, but fewer type II radio bursts. The onset heights of type II bursts and their association with wide CMEs suggest that the early lateral expansion of CMEs may play a key role in the generation of these radio bursts.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Anitha Ravishankar, Grzegorz Michalek
Summary: The study analyzed 38 non-interacting halo and partial halo CMEs parameters in STEREO/SECCHI images, and investigated their correlation with the generation of SEPs.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
N. Gopalswamy, J. Newmark, S. Yashiro, P. Makela, N. Reginald, N. Thakur, Q. Gong, Y. -H. Kim, K. -S. Cho, S. -H. Choi, J. -H. Baek, S. -C. Bong, H. -S. Yang, J. -Y. Park, J. -H. Kim, Y. -D. Park, J. -O. Lee, R. -S. Kim, E. -K. Lim
Summary: The BITSE mission utilized a balloon-borne instrument to observe the solar corona, providing crucial data on equatorial streamers and temperature flow rates. By comparing with existing SOHO data, it was found that BITSE observations were consistent with known properties of the solar corona.
Review
Geochemistry & Geophysics
Lynn B. Wilson, Alexandra L. Brosius, Natchimuthuk Gopalswamy, Teresa Nieves-Chinchilla, Adam Szabo, Kevin Hurley, Tai Phan, Justin C. Kasper, Noe Lugaz, Ian G. Richardson, Christopher H. K. Chen, Daniel Verscharen, Robert T. Wicks, Jason M. TenBarge
Summary: The Wind spacecraft, launched in 1994 as part of NASA's Heliophysics System Observatory, has become a standard for solar wind measurements with its longevity, diverse instrumentation, and high-resolution data. It has contributed to paradigm-shifting results in various fields of research, including statistical solar wind trends, magnetic reconnection, and extreme astrophysical phenomena.
REVIEWS OF GEOPHYSICS
(2021)
Article
Astronomy & Astrophysics
N. T. Shukure, S. B. Tessema, N. Gopalswamy
Summary: The study examined the long-term impact of solar irradiance on the Earth's climate, finding significant changes in both solar irradiance and mean surface temperature over evolutionary timescales. As time progresses, solar irradiance gradually increases, leading to substantial fluctuations in Earth's temperature.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
H. Xie, N. Gopalswamy, S. Akiyama
Summary: This study conducted a comprehensive statistical analysis on flux rope structures of coronal mass ejections (CMEs) near the Sun and at 1 au, finding that the hemispheric-helicity rule holds true for most events but not all. It was discovered that a significant number of events experienced large rotations between the magnetic cloud and CME flux rope axial orientations. Furthermore, the study revealed that a substantial portion of rotational events can be predicted based on the CME tilts.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Grzegorz Michalek, Nat Gopalswamy, Seiji Yashiro
Summary: This study investigates the temporal evolution of the yearly total mass-loss rate from the Sun through coronal mass ejections (CMEs). The results show that the CME mass included in the catalog reflects the actual mass-loss rate accurately. The study also highlights the importance of the mass-loss rate as an indicator of solar activity and space weather consequences.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
P. Vemareddy, P. Demoulin, K. Sasikumar Raja, J. Zhang, N. Gopalswamy, N. Vasantharaju
Summary: Using observations from the Solar Dynamics Observatory, this study examines an eruption of a hot-channel flux rope near the solar limb on February 9, 2015. The pre-eruptive structure is visible in EUV 131 angstrom images, showing two highly sheared loop structures that reconnect and form an eruptive hot channel. The eruption also produces radio bursts, and the flare ribbons clearly outline the boundary of the erupting flux rope.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Grzegorz Michalek, Nat Gopalswamy, Seiji Yashiro
Summary: This study analyzed the basic attributes of speed oscillations of CMEs from January 1996 to December 2019. The results showed that the oscillation parameters are closely related to the solar cycle phase and intensity, indicating their connection with the physical conditions inside CMEs and the interplanetary medium.
ASTROPHYSICAL JOURNAL LETTERS
(2022)
Article
Astronomy & Astrophysics
N. Swarnalingam, D. L. Wu, N. Gopalswamy
Summary: This study characterizes the responses of the ionosphere-thermosphere system during geomagnetic storms using TEC measurements and Ne retrieval profiles from GNSS receivers onboard LEO satellites. The results show consistent responses in TEC measurements from space-based and ground-based receivers during the storms. The study also reveals an interhemispheric asymmetry in the TEC and Ne responses, which correlates with the magnitude of FACs observed during the storms.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Zheyi Ding, Gang Lie, Robert W. Ebert, Maher A. Dayeh, Adolfo Santa Fe-Duenas, Mihir Desai, Hong Xie, N. Gopalswamy, A. Bruno
Summary: This study investigates the East-West asymmetry in large solar energetic particle (SEP) events using the 2D iPATH model. By fitting the longitudinal distributions of time-averaged fluence, it is found that the East-West asymmetry is primarily caused by the combined effect of an extended shock acceleration process and the evolution of magnetic field connection.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2022)
Article
Astronomy & Astrophysics
N. Gopalswamy, S. Yashiro, S. Akiyama, H. Xie, P. Makela, M-C Fok, C. P. Ferradas
Summary: This article reports on the solar and interplanetary causes of the third largest geomagnetic storm in solar cycle 24, which occurred on August 26, 2018. The study reveals that the prolonged acceleration of the coronal mass ejection, complex rotation of the magnetic flux rope, and high density in the interplanetary cloud are important factors contributing to the high intensity of the storm.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Fithanegest Kassa Dagnew, Nat Gopalswamy, Solomon Belay Tessema, Sachiko Akiyama, Seiji Yashiro
Summary: This study compares the width evolution of coronal mass ejections (CMEs) between solar cycle 23 and solar cycle 24, and finds that CMEs in solar cycle 24 have a significantly higher transition height and reach their peak width at larger distances from the Sun. This anomalous expansion is caused by the weak state of the heliosphere.
ASTROPHYSICAL JOURNAL
(2022)
Review
Environmental Sciences
Nat Gopalswamy
Summary: This chapter provides a brief review of the basic interactions between particles and magnetic fields, the processes occurring on the Sun relevant to space weather, and their impacts on Earth and the space environment. The strong societal impact of space weather on the complex world of telecommunication is emphasized.
Article
Astronomy & Astrophysics
Grzegorz Michalek, Nat Gopalswamy, Seiji Yashiro, Kostadinka Koleva
Summary: Coronal mass ejections (CMEs) are capable of causing severe geomagnetic disturbances, and their trajectory plays a crucial role in determining their geoeffectiveness. This study reveals that CMEs commonly experience deflection in the corona, which is heavily influenced by solar activity cycles and their phases. Additionally, the deflection of CMEs increases with both time and distance from the Sun.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Nat Gopalswamy, Grzegorz Michalek, Seiji Yashiro, Pertti Makela, Sachiko Akiyama, Hong Xie
Summary: The weakened state of the heliosphere during cycle 24 affected the width and occurrence of coronal mass ejections (CMEs). In cycle 25, the occurrence rate and properties of halo CMEs (HCMEs) are found to be intermediate between cycles 23 and 24, but closer to cycle 24. The strength of cycle 25 is expected to be similar to or slightly stronger than cycle 24, as indicated by polar-field precursor methods.
ASTROPHYSICAL JOURNAL LETTERS
(2023)
Article
Astronomy & Astrophysics
Sandeep Kumar, Dinesha V. Hegde, Nandita Srivastava, Nikolai V. Pogorelov, Nat Gopalswamy, Seiji Yashiro
Summary: This study reports on the observations of the 2012 October 5 stealth CME and finds clear evidence of continuous rotation and increasing tilt angle. The importance of observations from the Heliospheric Imager (HI) and the implications of CME tilt changes for space weather impact are highlighted.
ASTROPHYSICAL JOURNAL
(2023)
