Reconnection at the magnetopause of Saturn: Perspective from FTE occurrence and magnetosphere size

Flux transfer events observed at Mercury, Earth, and Jupiter are attributed to spatially and temporally limited events in which the magnetosheath and magnetospheric magnetic field become interconnected and magnetic flux is transported from the dayside to the lobes of the magnetotail. Examination of the Saturnian magnetopause at local times from 1000 to 1400 shows no evidence for this phenomenon. Nevertheless, we do find brief intervals during which the normal component of the magnetic field across the magnetopause becomes significantly enhanced for typically one to ten minutes. Magnetosheath electrons appear during these episodes of enhanced magnetic field normal components indicating that indeed the magnetosphere is connected to the magnetosheath by these magnetic bridges. To determine if this magnetic connection leads to a measurable transfer of magnetic flux from the dayside, we check the location of the magnetopause standoff distance for both northward and southward magnetosheath fields. In 71 crossings, we find no obvious dependence of the distance on the direction of the magnetosheath field, indicating that the direction of the interplanetary magnetic field is not a major factor in the determination of the location of the Saturnian magnetopause. This is unlike the position of the terrestrial magnetosphere that undergoes significant motion through reconnection with the interplanetary magnetic field.