A magnetic cloud is a transient event observed in the solar wind. It was defined in 1981 by Burlaga et al. 1981 as a region of enhanced magnetic field strength, smooth rotation of the magnetic field vector and low proton temperature. Magnetic clouds are a possible manifestation of a Coronal Mass Ejection (CME). The association between CMEs and magnetic clouds was made by Burlaga et al. in 1982 when a magnetic cloud was observed by Helios-1 two days after being observed by SMM. However, because observations near Earth are usually done by a single spacecraft, many CMEs are not seen as being associated with magnetic clouds. The typical structure observed for a fast CME by a satellite such as ACE is a fast-mode shock wave followed by a dense (and hot) sheath of plasma (the downstream region of the shock) and a magnetic cloud.
Read more about Magnetic Cloud: Other Characteristics, Other Types of Ejecta Observed At Earth
Famous quotes containing the words magnetic and/or cloud:
“We are in great haste to construct a magnetic telegraph from Maine to Texas; but Maine and Texas, it may be, have nothing important to communicate.”
—Henry David Thoreau (1817–1862)
“The cloud was so dark that it needed all the bright lights that could be turned upon it. But for four years there was a contagion of nobility in the land, and the best blood North and South poured itself out a libation to propitiate the deities of Truth and Justice. The great sin of slavery was washed out, but at what a cost!”
—M. E. W. Sherwood (1826–1903)