English: Image taken on August 11, 2000 by NASA's IMAGE spacecraft showing an ultraviolet glow from plasma surrounding our planet. The tail-like feature is formed when the magnetosphere is disturbed by a magnetic storm and enhanced convection "erodes" the outer plasmasphere, capturing plasma in the afternoon-dusk sector and transporting it outward and sunward toward the magnetopause.

The tail-like feature formed by entraining of plasma by outward convective flow is know as the "duskside bulge."

Another noteworthy feature in the picture is the faint oval inside a bigger and brighter oval (ionosphere). This faint oval is caused by ultraviolet radiation from aurora borealis. Additionally one can see an Earth's shadow and notice how the nightside of plasmasphere extends farther than the dayside.

For fuller description see: http://pluto.space.swri.edu/image/glossary/plasmasphere2.html