Geomagnetic storms are global phenomena that result from enhanced depositions of solar wind energy and momentum into the ionosphere-thermosphere system that can cause global increases in geomagnetic activity and the aurora to be observed worldwide. Although geomagnetic storms can occur during any phase of the solar cycle, they are usually more intense and occur more often during periods of high solar activity. Extreme geomagnetic storms are usually caused by fast Coronal Mass Ejections (CMEs) with intense southward Interplanetary Magnetic Field (IMF) components. However, the Sun has shown in the past two decades a remarkable quiet condition, with very few significant events. In the past two decades, the most severe geomagnetic storms were the Halloween storms of 2003, and St. Patrick’s Day storms of 2013 and 2015.This Research Topic focuses on the extreme geomagnetic storm of May 2024, the most severe event in the past twenty years. This event is unique because it occurred during a period of unprecedented amounts of heliophysics data sets collected by satellites in space (near-Sun region, solar wind, magnetosphere), upper atmosphere at low-Earth orbit (exosphere, thermosphere, ionosphere), and on the ground (radars, magnetic field observations and geomagnetically induced currents). Such a plethora of data sets allows for a multi-faceted investigation of enhanced Sun-Earth connections and the subsequent geomagnetic activity and space weather response. The May 2024 storm also brought worldwide attention because the resulting aurora could be seen in many lower latitude regions, such as the United States, Mexico, Portugal, Spain, Italy, Japan, South Africa, Australia, Argentina, Chile, and Uruguay. The main goal of this Research Topic is to bring together contributions focusing on understanding the causes and the subsequent worldwide space weather/space physics effects caused by the May 2024 storm. We invite studies that focus on the following topics:- solar activity, including the active regions that generated the solar flares and CMEs- solar wind, IMF, and energetic particle observations near the Sun, at 1 AU, and beyond- inner magnetosphere response: radiation belts, plasma populations, and magnetic field at geosynchronous distance- ionospheric response: plasma bubble, ionospheric irregularities, and impacts on Global Navigation Satellite System (GNSS)- thermospheric response: satellite orbital drag at low-Earth orbit- auroral observations around the world (optical instruments and naked eye) - ground magnetic field response, effects on technologies and observations of Geomagnetically Induced Currents (GICs).We encourage submissions that compare many local/global events in May 2024 with historical events (e.g., March 1989, the Halloween events of 2003, St. Patrick’s Day storms of 2013 and 2015). We also encourage studies focusing on the interaction of the main CME with other planets and solar wind bodies (moons) and other regions of the heliosphere. Contributions focusing on simulation studies are also encouraged. Finally, we encourage submissions with focus on predictions of extreme geomagnetic storms for the remaining period of solar cycle 25 and beyond. Thus, the main goal of this Research Topic is to advance our understanding of extreme geomagnetic storms including the comparison of the May 2004 storm with other historical events.We wish to name that event as the Extreme Gannon Geomagnetic Storm of May 2024 after Dr. Jennifer Gannon, who unfortunately passed away a week before the event. This Research Topic is also a tribute to the life and work of Jenn, who made significant contributions to the field of space science and space weather in her regrettably abbreviated career.
Geomagnetic storms are global phenomena that result from enhanced depositions of solar wind energy and momentum into the ionosphere-thermosphere system that can cause global increases in geomagnetic activity and the aurora to be observed worldwide. Although geomagnetic storms can occur during any phase of the solar cycle, they are usually more intense and occur more often during periods of high solar activity. Extreme geomagnetic storms are usually caused by fast Coronal Mass Ejections (CMEs) with intense southward Interplanetary Magnetic Field (IMF) components. However, the Sun has shown in the past two decades a remarkable quiet condition, with very few significant events. In the past two decades, the most severe geomagnetic storms were the Halloween storms of 2003, and St. Patrick’s Day storms of 2013 and 2015.This Research Topic focuses on the extreme geomagnetic storm of May 2024, the most severe event in the past twenty years. This event is unique because it occurred during a period of unprecedented amounts of heliophysics data sets collected by satellites in space (near-Sun region, solar wind, magnetosphere), upper atmosphere at low-Earth orbit (exosphere, thermosphere, ionosphere), and on the ground (radars, magnetic field observations and geomagnetically induced currents). Such a plethora of data sets allows for a multi-faceted investigation of enhanced Sun-Earth connections and the subsequent geomagnetic activity and space weather response. The May 2024 storm also brought worldwide attention because the resulting aurora could be seen in many lower latitude regions, such as the United States, Mexico, Portugal, Spain, Italy, Japan, South Africa, Australia, Argentina, Chile, and Uruguay. The main goal of this Research Topic is to bring together contributions focusing on understanding the causes and the subsequent worldwide space weather/space physics effects caused by the May 2024 storm. We invite studies that focus on the following topics:- solar activity, including the active regions that generated the solar flares and CMEs- solar wind, IMF, and energetic particle observations near the Sun, at 1 AU, and beyond- inner magnetosphere response: radiation belts, plasma populations, and magnetic field at geosynchronous distance- ionospheric response: plasma bubble, ionospheric irregularities, and impacts on Global Navigation Satellite System (GNSS)- thermospheric response: satellite orbital drag at low-Earth orbit- auroral observations around the world (optical instruments and naked eye) - ground magnetic field response, effects on technologies and observations of Geomagnetically Induced Currents (GICs).We encourage submissions that compare many local/global events in May 2024 with historical events (e.g., March 1989, the Halloween events of 2003, St. Patrick’s Day storms of 2013 and 2015). We also encourage studies focusing on the interaction of the main CME with other planets and solar wind bodies (moons) and other regions of the heliosphere. Contributions focusing on simulation studies are also encouraged. Finally, we encourage submissions with focus on predictions of extreme geomagnetic storms for the remaining period of solar cycle 25 and beyond. Thus, the main goal of this Research Topic is to advance our understanding of extreme geomagnetic storms including the comparison of the May 2004 storm with other historical events.We wish to name that event as the Extreme Gannon Geomagnetic Storm of May 2024 after Dr. Jennifer Gannon, who unfortunately passed away a week before the event. This Research Topic is also a tribute to the life and work of Jenn, who made significant contributions to the field of space science and space weather in her regrettably abbreviated career.