The radio source J1819+3845 underwent a period of extreme interstellar scintillation between circa 1999 and 2007 . The plasma structure responsible for this scintillation was determined to be just 1 - 3 pc from the solar system and to posses a density of n _ { e } \sim 10 ^ { 2 } cm ^ { -3 } that is three orders of magnitude higher than the ambient interstellar density ( 8 ) . Here we present radio-polarimetric images of the field towards J1819+3845 at wavelengths of 0.2 , 0.92 and 2 m. We detect an elliptical plasma globule of approximate size 1 ^ { \circ } \times \gtrsim 2 ^ { \circ } ( major-axis position angle of \approx - 40 ^ { \circ } ) , via its Faraday-rotation imprint ( \approx 15 { rad } { m } ^ { -2 } ) on the diffuse Galactic synchrotron emission . The extreme scintillation of J1819+3845 was most likely caused at the turbulent boundary of the globule ( J1819+3845 is currently occulted by the globule ) . The origin and precise nature of the globule remain unknown . Our observations are the first time plasma structures that likely cause extreme scintillation have been directly imaged .