Although space weather forecasts are not normally featured on the evening news, space weather does impact life on Earth in many ways. The space plasma, which is the “kitchen” of the space weather, is a very unique composition of different kinds of plasmas and electromagnetic fields. It covers a huge plasma energy range, with spatial and time variations of many orders of magnitude. Each of these populations has distinct features and contributes in a different way to the dynamic and energetic processes of the space plasma. Each has a unique coupling mechanism with surrounding plasma and electromagnetic fields, providing a very noticeable contribution to the physics of the space weather. Space weather was identified as one of the nine natural hazards that pose the greatest threat to the nation’s security in the US Presidential Policy Directive.