Solar Cycle Changes in the Photochemistry of the Ionosphere and Thermosphere

Richards, P. G.

doi:10.1002/9781118704417.ch3

Cited by 4 publications

(5 citation statements)

References 37 publications

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“…Model outflow from these higher regions shown in panels 2a and 2b results in outflowing MI dominated by nearly equal parts of N 2 + and NO + , each generally more populous than O 2 + by a factor of >3, irrespective of solar and geomagnetic activity (see Table S10 in the SI for the SAMI3 and WACCM-X model run parameters and intervals). That O 2 + /(N 2 + + NO + ) < 1, characteristic of the ionospheric observations noted above, is shown by several other ionospheric models (Köhnlein, 1989;Cannata, 1990;Richards, 2013; see also Hoegy et al, 1991). We note further that in an investigation demonstrating solar cycle variation of ionospheric MI by Richards (2013), who used yet a different model, O 2 + was shown to decrease relative to N 2 + and NO + abovẽ 280-290 km.…”

Section: Observationssupporting

confidence: 67%

“…That O 2 + /(N 2 + + NO + ) < 1, characteristic of the ionospheric observations noted above, is shown by several other ionospheric models (Köhnlein, 1989;Cannata, 1990;Richards, 2013; see also Hoegy et al, 1991). We note further that in an investigation demonstrating solar cycle variation of ionospheric MI by Richards (2013), who used yet a different model, O 2 + was shown to decrease relative to N 2 + and NO + abovẽ 280-290 km. Results from these various models are generally consistent, but the public access to WACCM-X and SAMI3 allows interested readers to look further into the MI compositional aspects demonstrated here.…”

Section: Observationssupporting

confidence: 67%

“…Recent observations (e.g., Andersson et al, 2004;André & Cully, 2012;Haaland et al, 2012;Wilson et al, 2004;Yu & Ridley, 2013) collectively demonstrate that both the dayside cusp and the nightside auroral zone can contribute substantial quantities of outflowing ions (from cold, ~eV, to tens of eV energies) to the total ion plasma population throughout the magnetosphere, as well as to the many energized ionospheric origin ions that are quickly lost downtail (see, e.g., . André and Cully (2012) state that although (Köhnlein, 1989;Cannata, 1990;Richards, 2013; see also Hoegy et al, 1991). We note further that in an investigation demonstrating solar cycle variation of ionospheric MI by Richards (2013), who used yet a different model, O 2 + was shown to decrease relative to N 2 + and NO + above ~280-290 km.…”

Section: Observationsmentioning

confidence: 49%

“…Calculations in Figure 2b from SAMI3 (at https://ccmc.gsfc.nasa.gov/models/modelinfo.php?model= SAMI3) and WACCM-X (at https://www2.hao.ucar.edu/modeling/waccm-x) show that although O 2 + can contribute significantly between~100 and 150 km, it becomes a minor component at altitudes higher thañ 300-450 km and latitudes ≥50°, locations where ionospheric outflow ion composition is determined. That O 2 + /(N 2 + + NO + ) < 1, characteristic of the ionospheric observations noted above, is shown by several other ionospheric models (Köhnlein, 1989;Cannata, 1990;Richards, 2013; see also Hoegy et al, 1991). That O 2 + /(N 2 + + NO + ) < 1, characteristic of the ionospheric observations noted above, is shown by several other ionospheric models (Köhnlein, 1989;Cannata, 1990;Richards, 2013; see also Hoegy et al, 1991).…”

Section: Observationsmentioning

confidence: 78%

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

Christon¹,

Hamilton

Mitchell

et al. 2020

JGR Space Physics

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We examine long-term suprathermal, singly charged heavy ion composition measured at three planets using functionally identical charge-energy-mass ion spectrometers, one on Geotail, orbiting Earth at 9-30 Re, the other on Cassini, in interplanetary space, during Jupiter flyby, and then in orbit around Saturn. O + , a principal suprathermal (~80-220 keV/e) heavy ion in each magnetosphere, derives primarily from outflowing ionospheric O + at Earth, but mostly from satellites and rings at Jupiter and Saturn. Comparable amounts of Iogenic O + and S + are present at Jupiter. Ions escaping the magnetospheres: O + and S + at Jupiter; C + , N + , O + , H 2 O + , 28 M + (possibly an aggregate of the molecular ions, MI, CO + , N 2 + , HCNH + , and/or C 2 H 4 + ), and O 2 + at Saturn; and N + , O + , N 2 + , NO + , O 2 + , and Fe + at Earth. Generally, escaped atomic ions (MI) at Earth and Saturn have similar (higher) ratios to O + compared to their magnetospheric ratios; Saturn's H 2 O + and Fe + ratios are lower. At Earth, after O + and N + , ionospheric origin N 2 + , NO + , and O 2 + (with proportions~0.9:1.0:0.2) dominate magnetospheric heavy ions, consistent with recent high-altitude/latitude ionospheric measurements and models; average ion count rates correlate positively with geomagnetic and solar activity. At~27-33 amu/e, Earth's MIs dominate over lunar pickup ions (PUIs) in the magnetosphere; MIs are roughly comparable to lunar PUIs in the magnetosheath, and lunar PUIs dominate over MIs beyond Earth's bow shock. Lunar PUIs are detected at~39-48 amu/e in the lobe and possibly in the plasma sheet at very low levels.Plain Language Summary Some of the air we breathe, a gas of~78% N 2 and~21% O 2 molecules, expands into the high-altitude atmosphere, the thermosphere, and becomes ionized by sunlight and charged particles from space to become the ionosphere. Molecules can break up into their component atoms or combine with other ions to form other molecules. Some ionospheric ions flow out into space, mostly during geomagnetic disturbances, and are further energized. Magnetospheres, plasma bubbles filled with these energized particles, form around planets with magnetic fields, like the Earth whose magnetic field stands off the steady stream of ions and electrons from the Sun called the solar wind. Particles inside the bubbles can be planet or satellite origin, and outside the bubble, they are mostly Sun origin. However, some inside get out and some outside get in. Improved ion measurements from space give us information to help unravel both the outflowing particles' interactions on the way out and when and how ions escape or penetrate magnetospheres. Planets' satellites and rings also contribute ionized and neutral particles to the mix, making various determinations more difficult than others. Ions from solar wind and sunlight impacting Earth's satellite, the Moon, which spends most of its time outside Earth's magnetosphere, dominate ion composition at some masses and energies there while contributing little overall inside...

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Section: Observationssupporting

confidence: 67%

Section: Observationssupporting

confidence: 67%

Section: Observationsmentioning

confidence: 49%

Section: Observationsmentioning

confidence: 78%

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

Christon¹,

Hamilton

Mitchell

et al. 2020

JGR Space Physics

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“…Table S10 in the SI for the SAMI3 and WACCM-X model run parameters and intervals). That O 2 + /(N 2 + + NO + ) < 1, characteristic of the ionospheric observations noted above, is shown by several other ionospheric models (Koehlein, 1989;Cannata, 1990;Richards, 2013; see also Hoegy, 1991). We note further that in an investigation demonstrating solar cycle variation of ionospheric MI by Richards (Wilson et al, 2002), CO, CO 2 , H 2 O, and O 2 from Ganymede, Europa, and Callisto (e.g., Cooper et al, 2001), or Jupiter family comets (Bockelée-Morvan, 2011), and/or NaCl and/or NaOH from Io (McEwan et al, 2007;Kuppers and Schneider, 2000).…”

Section: Spacecraft and Instrumentssupporting

confidence: 57%

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

Christon

Hamilton

Mitchell³

et al. 2019

Preprint

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Earth's magnetospheric N 2 + , NO + , and O 2 + (~43%, ~46%, and ~10%, respectively) argue for ionospheric ion outflow at ~350-550 km altitude Outside Earth and Saturn's magnetospheres, levels of heavy molecular (atomic) ions relative to O + are higher (similar) compared to inside Heavy molecular to lunar pickup ion ratios are >>1, ~1, and <1 in Earth's magnetosphere, the sheath, and the solar wind, respectively Please Note: Full page versions of the Figures (most with their full caption) are inserted on the first page after the first citation. My version of MSWord inserted extra blank lines (which I could not adjust) at the insertion point.

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CubeSat measurements of thermospheric plasma: spacecraft charging effects on a plasma analyzer

et al. 2022

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Spacecraft charging affects the accuracy of in-situ plasma measurements in space. We investigate the impact of spacecraft charging on upper thermospheric plasma measurements captured by a 2U CubeSat called Phoenix. Using the Spacecraft Plasma Interactions Software (SPIS), we simulate dayside surface potentials of − 0.6 V, and nightside potentials of − 0.2 V. We also observe this charging mechanism in the distribution function captured by the Ion and Neutral Mass Spectrometer (INMS) on-board Phoenix. Whilst negative charging in the dense ionosphere is known, the diurnal variation in density and temperature has resulted in dayside potentials that are smaller than at night. We apply charging corrections in accordance with Liouville’s theorem and employ a least-squares fitting routine to extract the plasma density, bulk speed, and temperature. Our routine returns densities that are within an order of magnitude of the benchmarks above, but they carry errors of at least 20%. All bulk speeds are greater than the expected range of 60–120 m/s and this could be due to insufficient charging corrections. Our parameterised ion temperatures are lower than our empirical benchmark but are in-line with other in-situ measurements. Temperatures are always improved when spacecraft charging corrections are applied. We mostly attribute the shortcomings of the findings to the ram-only capture mode of the INMS. Future work will improve the fitting routine and continue to cross-check with other in-flight data.

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Solar Cycle Changes in the Photochemistry of the Ionosphere and Thermosphere

Cited by 4 publications

References 37 publications

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

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

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

CubeSat measurements of thermospheric plasma: spacecraft charging effects on a plasma analyzer

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