A corona discharge is an electrical discharge caused by the ionization of a fluid such as air surrounding a conductor carrying a high voltage. It represents a local region where the air has undergone electrical breakdown and become conductive, allowing charge to continuously leak off the conductor into the air. A corona discharge occurs at locations where the strength of the electric field around a conductor exceeds the dielectric strength of the air. It is often seen as a bluish glow in the air adjacent to pointed metal conductors carrying high voltages, and emits light by the same mechanism as a gas discharge lamp. Corona discharges can also happen in weather, such as thunderstorms, where objects like ship masts or airplane wings have a charge significantly different from the air around them.

किसी विद्युतचालक के आसपास के तरल के आयनित होने के कारण विद्युत विसर्जन को किरीट विसर्जन या 'कोरोना डिस्चार्ज' कहते हैं। किरीट विसर्जन उस स्थिति में होता है जब चालक के आसपास विद्युत क्षेत्र की तीव्रता का मान इतना हो कि वहाँ एक चालक क्षेत्र बन जाय किन्तु इतना अधिक भी न हो कि विद्युत भंजन की स्थिति उत्पन्न हो।