<P> where pressure P is in nPa (nanopascals), n is the density in particles / cm and V is the speed in km / s of the solar wind . </P> <P> Both the fast and slow solar wind can be interrupted by large, fast - moving bursts of plasma called interplanetary coronal mass ejections, or ICMEs . ICMEs are the interplanetary manifestation of solar coronal mass ejections, which are caused by release of magnetic energy at the Sun . CMEs are often called "solar storms" or "space storms" in the popular media . They are sometimes, but not always, associated with solar flares, which are another manifestation of magnetic energy release at the Sun . ICMEs cause shock waves in the thin plasma of the heliosphere, launching electromagnetic waves and accelerating particles (mostly protons and electrons) to form showers of ionizing radiation that precede the CME . </P> <P> When a CME impacts the Earth's magnetosphere, it temporarily deforms the Earth's magnetic field, changing the direction of compass needles and inducing large electrical ground currents in Earth itself; this is called a geomagnetic storm and it is a global phenomenon . CME impacts can induce magnetic reconnection in Earth's magnetotail (the midnight side of the magnetosphere); this launches protons and electrons downward toward Earth's atmosphere, where they form the aurora . </P> <P> ICMEs are not the only cause of space weather . Different patches on the Sun are known to give rise to slightly different speeds and densities of wind depending on local conditions . In isolation, each of these different wind streams would form a spiral with a slightly different angle, with fast - moving streams moving out more directly and slow - moving streams wrapping more around the Sun . Fast moving streams tend to overtake slower streams that originate westward of them on the Sun, forming turbulent co-rotating interaction regions that give rise to wave motions and accelerated particles, and that affect Earth's magnetosphere in the same way as, but more gently than, CMEs . </P>

Trapped gas within the sun is known as