Physics of geospace storms

Abstract

A review of our knowledge about the coupling of solar-terrestrial processes, manifestations of geospace storms, and variations in space weather is presented. Space weather effects are analyzed within the system paradigm concept. The system where geospace storms occur is a Sun–interplanetary medium–magnetosphere–ionosphere–atmosphere–Earth (interior spheres) aggregate (SIMMIAE). An early twenty-first- century geospace superstorm that occurred on November 7 – 10, 2004, is examined in detail. Clustered instrument observations of this storm effects are presented. The investigation of the physical effects of geospace storms is noted to be the most important field of study in space geophysics. The problem of subsystem coupling in the SIMMIAE system during a geospace storm is interdisciplinary in nature. Its solution requires an application of the system approach. The problem has a multifactor character. The subsystem response is determined by the simultaneous (synergetic) impact of a few disturbing factors. It is important to note that the SIMMIAE is an open, nonlinear, and nonstationary system. Within it, direct coupling and feedback processes, positive and negative linkages operate. Due to the myriads of manifestations of geospace storms, because of the unique nature of each storm, the investigation of occurring physical effects is far from complete. In addition to a thorough investigation of the storm’s physical effects, there is an urgent need to model and forecast the storms adequately and in detail. The solution to these problems will facilitate the survival and steady progress of our civilization, relying more and more on new state-of-the-art technology. The more technologically reliant our society is, the more vulnerable the civilization's infrastructure to solar and geospace storm impacts becomes. A classification of geostorms based on Akasofu's epsilon parameter has been advanced. Six types of geostorm have been introduced, and a geostorm index has been suggested. A classification of ionospheric storms and disturbances based on the magnitude of variations in the peak density of the F2 layer has been suggested. Five types of the ionospheric storm have been introduced. An ionospheric index characterizing the intensity of negative and positive ionospheric storms has been suggested. A classification of ionospheric storms and disturbances based on the magnitude of variations in the lower-ionosphere electron density has been proposed. Six types of the positive ionospheric storm have been introduced. The appropriate ionospheric index has been suggested. The physics-based model of the evolution of each group of ionospheric storms and disturbances has been determined. The linkages among magnetic, ionospheric, and atmospheric storms, as well as electric field disturbances, have been shown.