Discovery of suprathermal Fe⁺ in Saturn's magnetosphere

Fe embedded in ice: The impacts of sublimation and energetic particle bombardment

“…The Cassini CHEMS instrument has observed large quantities of superthermal ions with a mass around 16 amu (Christon et al, 2013). Assuming these ions to be O þ , and taking the average measured energy to be 100 keV, use of equations 1-6 (note that in this case M t /M p ¼ 3.5, so that α in Eq.…”

“…Fe 2 O 3 ) arising from the bombardment of the rings by interplanetary dust particles (Cuzzi et al, 2009). Very recently, superthermal ion measurements using the CHEMS ion spectrometer on the Cassini spacecraft have shown the presence of heavy ions at mass 56 amu, tentatively identified as Fe þ , in the Saturnian magnetosphere beyond the main rings (Christon et al, 2013). One explanation for this intriguing observation is sputtering of Fe from the icy particles in the rings, followed by photo-ionisation of the resulting Fe atoms.…”

Suprathermal Magnetospheric Atomic and Molecular Heavy Ions at and Near Earth, Jupiter, and Saturn: Observations and Identification

“…The complementary comprehensive studies by Yau et al (1993) and Peterson et al (1994) clearly identified N 2 + and NO + as the principal, comparably abundant, outflowing ionospheric Mass-30 (~27-33 amu) molecular ion species in high-latitude, high-altitude measurements at 2-3 Re. As discovered and presented in this and recent investigations Christon et al, 2015), we now understand that atomic and molecular ion energy loss measurements in this class of time-of-flight total-energy instrument must be analyzed differently. and Christon, Hamilton, et al (1994) referred to escaped ionospheric MI in Earth's magnetosphere as NO + and O 2 + , reflecting the earlier observations and identification by Klecker et al (1986) and Gloeckler and Hamilton (1987).…”

“…The improved composition assessment of the long-term MI component of outflown ionospheric MI fluxes observed in Earth's magnetosphere presented herein is intended to help focus planning choices for future thermosphere-ionosphere-magnetosphere observations. Of note, Earth's ionospheric meteoric metal neutral and ion layers at~80-120 km altitude include Na, Mg, Al, Si, K, Ca, Ti, and Fe (Plane et al, 2018), many of the expected lunar PUIs (see also our discussions in Christon et al, 2015Christon et al, , 2017. A primary purpose of this paper is to clearly identify which MI ultimately flow out of Earth's ionosphere and are subsequently incorporated into Earth's magnetospheric ion population.…”

“…Note that we refer to Saturn's R < 20 Rs and R > R BS data as Saturn's "Sphere" and "Solar Wind" data, respectively. Christon et al, 2015), noncommittal species descriptors are used for all molecular ion species in this figure. Spillover from 30 Ma + ions into 28 Ma + ions is unlikely, as TOF variations are physically limited toward longer TOFs.…”