Cusp observation at Saturn's high-latitude magnetosphere by the Cassini spacecraft

• Published in: Geophysical research letters 2014-03, Vol.41 (5), p.1382-1388
• Main Authors: Jasinski, J. M., Arridge, C. S., Lamy, L., Leisner, J. S., Thomsen, M. F., Mitchell, D. G., Coates, A. J., Radioti, A., Jones, G. H., Roussos, E., Krupp, N., Grodent, D., Dougherty, M. K., Waite, J. H.
• Format: Article
• Language: English
• Subjects: Alignment; Amplification; Astrophysics; Aérospatiale, astronomie & astrophysique; Cassini; Cassini mission; Compressing; cusp; Cusps; Dispersion; Dispersions; Distance; Earth Sciences; Energy; Geophysics; Instruments; Latitude; Magnetopause; Magnetopause reconnection; Magnetosphere; Magnetospheres; Magnetospheric cusp; Noon; Onboard; Physical, chemical, mathematical & earth Sciences; Physics; Physique, chimie, mathématiques & sciences de la terre; Pitch (inclination); Planetary magnetospheres; plasma; Radiation; reconnection; Research Letter; Saturn; Sciences of the Universe; Shock; Signatures; Solar wind; Space science, astronomy & astrophysics; Spacecraft; Stepped; Trajectories
• ISSN: 0094-8276; 1944-8007; 1944-8007
• DOI: 10.1002/2014GL059319

We report on the first analysis of magnetospheric cusp observations at Saturn by multiple in situ instruments onboard the Cassini spacecraft. Using this we infer the process of reconnection was occurring at Saturn's magnetopause. This agrees with remote observations that showed the associated auroral signatures of reconnection. Cassini crossed the northern cusp around noon local time along a poleward trajectory. The spacecraft observed ion energy‐latitude dispersions—a characteristic signature of the terrestrial cusp. This ion dispersion is “stepped,” which shows that the reconnection is pulsed. The ion energy‐pitch angle dispersions suggest that the field‐aligned distance from the cusp to the reconnection site varies between ∼27 and 51 RS. An intensification of lower frequencies of the Saturn kilometric radiation emissions suggests the prior arrival of a solar wind shock front, compressing the magnetosphere and providing more favorable conditions for magnetopause reconnection. Key Points We observe evidence for reconnection in the cusp plasma at Saturn We present evidence that the reconnection process can be pulsed at Saturn Saturn's cusp shows similar characteristics to the terrestrial cusp