It is discussed in this paper some basic concepts related to space weather in the near-Earth space environment. Due to technological developments in the past years, space weather has become an important subject of research. The achievements in this area are mainly related to its applicability to the safety of technological systems in space and on the ground. Among several subjects of space weather researchers' interest is the investigation of how perturbations in the interplanetary medium, as a consequence of solar variability, affect the Earth's magnetic field. The effects of such variabilities can be observed on the ground through measurements of magnetometers on the ground and in the near-Earth space environment, for example, the auroras. Some aspects of a particular case of solar disturbances, namely interplanetary shocks, are briefly reviewed. A real event with intense geomagnetic activity is simulated by a global magnetohydrodynamic (MHD) code. Simulation results agree well with ground magnetometer data. The importance of global MHD simulations in developing space weather prediction models is emphasized.
Keywords:
space weather; magnetosphere-ionosphere interactions; numerical simulations and observations
