A corona igniter for emitting a radio frequency electric field to ionize a fuel-air mixture and provide a corona discharge, comprising: a central electrode formed of an electrically conductive material for receiving the high radio frequency voltage and emitting the radio frequency electric field to ionize the fuel-air mixture and provide said corona discharge, a shell formed of a metal material extending along said central electrode, said shell extending longitudinally from an upper shell end to a lower shell end, an insulator formed of an electrically insulating material disposed between said central electrode and said shell, said insulator including an insulator outer surface facing away from said central electrode and extending longitudinally from an insulator upper end to an insulator nose end and presenting an abruption extending radially outward relative to said central electrode, and wherein said insulator includes a protrusion extending radially away from said central electrode and said abruption is a flank of said protrusion facing said shell wherein said shell includes a shell bore extending longitudinally from said upper shell end to said lower shell end, said shell bore presents a shell bore diameter (D s) said insulator includes an insulator nose region extending from adjacent said lower shell end to said insulator nose end, and said insulator nose region presents an insulator nose diameter (D n), and said insulator outer surface includes a smooth transition providing said abruption, the corona igniter being characterized in that said shell bore diameter (D s) is greater than said insulator nose diameter (D n), and in that said shell and said insulator present a shell gap therebetween filled, during operation, with an ionized gas including positive ions and negative ions and wherein a plurality of said negative ions move along said insulator outer surface and through said insulating material to said abruption and wherein said abruption repels said negative ions. a central electrode formed of an electrically conductive material for receiving the high radio frequency voltage and emitting the radio frequency electric field to ionize the fuel-air mixture and provide said corona discharge, a shell formed of a metal material extending along said central electrode, said shell extending longitudinally from an upper shell end to a lower shell end, an insulator formed of an electrically insulating material disposed between said central electrode and said shell, said insulator including an insulator outer surface facing away from said central electrode and extending longitudinally from an insulator upper end to an insulator nose end and presenting an abruption extending radially outward relative to said central electrode, and wherein said insulator includes a protrusion extending radially away from said central electrode and said abruption is a flank of said protrusion facing said shell wherein said shell includes a shell bore extending longitudinally from said upper shell end to said lower shell end, said shell bore presents a shell bore diameter (D s) said insulator includes an insulator nose region extending from adjacent said lower shell end to said insulator nose end, and said insulator nose region presents an insulator nose diameter (D n), and said insulator outer surface includes a smooth transition providing said abruption, the corona igniter being characterized in that said shell bore diameter (D s) is greater than said insulator nose diameter (D n), and in that said shell and said insulator present a shell gap therebetween filled, during operation, with an ionized gas including positive ions and negative ions and wherein a plurality of said negative ions move along said insulator outer surface and through said insulating material to said abruption and wherein said abruption repels said negative ions.