Composition and structure of the ionosphere and thermosphere

T. E. Cravens, Roger Yelle, J. E. Wahlund, D. E. Shemansky, A. F. Nagy

Research output: Chapter in Book/Report/Conference proceedingChapter

23 Citations (Scopus)

Abstract

Airglow emissions, radio and solar occultation data from the Voyager mission over a quarter of a century ago provided the main source of information on the composition and structure of Titan's upper atmosphere and ionosphere until October 2004, when the Cassini Orbiter first encountered Titan during the Ta fly-by. During this encounter, in situ measurements were made by many instruments onboard the Orbiter, including the Ion and Neutral Mass Spectrometer (INMS), the Radio Wave and Plasma Wave Spectrometer (RPWS), the Magnetometer (MAG), and the Cassini Plasma Spectrometer (CAPS). For example, INMS measurements confirmed that the major neutral species were molecular nitrogen and methane. Other species detected included mole cular hydrogen, acetylene, ethylene, benzene, and propane. The Langmuir probe part of the RPWS experiment observed substantial ionospheric electron densities and measured electron temperatures significantly exceeding the neutral temperature. A large set of data on the upper atmosphere and ionosphere has been collected during the many Titan encounters following Ta. The first composition measurements for the ionosphere were made by INMS during the outbound leg of the T5 pass in April 2005. A rich and complex ion-neutral chemistry scheme was predicted prior to the Cassini mission and the INMS composition data indeed revealed the presence of a very large number of ion species, both predicted and unpre-dicted. Stellar occultation measurements made by the Cassini Ultraviolet Spectrometer (UVIS) provided important information on the structure and composition of Titan's upper atmosphere, and radio occultation measurements made by the Radio Science Subsystem (RSS) revealed the existence of a substantial ionosphere even for altitudes below 1000 km. The discovery of negative ions in the ionosphere was also very exciting. A vigorous modeling effort aimed at explaining the structure and composition of the upper atmosphere and ionosphere is helping to put the data into a broader theoretical context. For example, solar extreme ultraviolet and x-ray radiation and energetic electrons from Saturn's magnetosphere interact with the upper atmosphere producing the ionosphere and initiating a complex neutral and ion chemistry that has important effects extending deep into the atmosphere.

Original languageEnglish (US)
Title of host publicationTitan from Cassini-Huygens
PublisherSpringer Netherlands
Pages259-295
Number of pages37
ISBN (Print)9781402092145
DOIs
StatePublished - 2010

Fingerprint

thermosphere
ionospheres
upper atmosphere
Titan
upper ionosphere
mass spectrometers
ions
radio occultation
radio waves
occultation
spectrometers
plasma waves
encounters
Cassini mission
stellar occultation
ionospheric electron density
chemistry
ultraviolet spectrometers
airglow
Saturn

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

Cravens, T. E., Yelle, R., Wahlund, J. E., Shemansky, D. E., & Nagy, A. F. (2010). Composition and structure of the ionosphere and thermosphere. In Titan from Cassini-Huygens (pp. 259-295). Springer Netherlands. https://doi.org/10.1007/978-1-4020-9215-2_11

Composition and structure of the ionosphere and thermosphere. / Cravens, T. E.; Yelle, Roger; Wahlund, J. E.; Shemansky, D. E.; Nagy, A. F.

Titan from Cassini-Huygens. Springer Netherlands, 2010. p. 259-295.

Research output: Chapter in Book/Report/Conference proceedingChapter

Cravens, TE, Yelle, R, Wahlund, JE, Shemansky, DE & Nagy, AF 2010, Composition and structure of the ionosphere and thermosphere. in Titan from Cassini-Huygens. Springer Netherlands, pp. 259-295. https://doi.org/10.1007/978-1-4020-9215-2_11
Cravens TE, Yelle R, Wahlund JE, Shemansky DE, Nagy AF. Composition and structure of the ionosphere and thermosphere. In Titan from Cassini-Huygens. Springer Netherlands. 2010. p. 259-295 https://doi.org/10.1007/978-1-4020-9215-2_11
Cravens, T. E. ; Yelle, Roger ; Wahlund, J. E. ; Shemansky, D. E. ; Nagy, A. F. / Composition and structure of the ionosphere and thermosphere. Titan from Cassini-Huygens. Springer Netherlands, 2010. pp. 259-295
@inbook{70a94a00a7c947be8a72c67420f80d00,
title = "Composition and structure of the ionosphere and thermosphere",
abstract = "Airglow emissions, radio and solar occultation data from the Voyager mission over a quarter of a century ago provided the main source of information on the composition and structure of Titan's upper atmosphere and ionosphere until October 2004, when the Cassini Orbiter first encountered Titan during the Ta fly-by. During this encounter, in situ measurements were made by many instruments onboard the Orbiter, including the Ion and Neutral Mass Spectrometer (INMS), the Radio Wave and Plasma Wave Spectrometer (RPWS), the Magnetometer (MAG), and the Cassini Plasma Spectrometer (CAPS). For example, INMS measurements confirmed that the major neutral species were molecular nitrogen and methane. Other species detected included mole cular hydrogen, acetylene, ethylene, benzene, and propane. The Langmuir probe part of the RPWS experiment observed substantial ionospheric electron densities and measured electron temperatures significantly exceeding the neutral temperature. A large set of data on the upper atmosphere and ionosphere has been collected during the many Titan encounters following Ta. The first composition measurements for the ionosphere were made by INMS during the outbound leg of the T5 pass in April 2005. A rich and complex ion-neutral chemistry scheme was predicted prior to the Cassini mission and the INMS composition data indeed revealed the presence of a very large number of ion species, both predicted and unpre-dicted. Stellar occultation measurements made by the Cassini Ultraviolet Spectrometer (UVIS) provided important information on the structure and composition of Titan's upper atmosphere, and radio occultation measurements made by the Radio Science Subsystem (RSS) revealed the existence of a substantial ionosphere even for altitudes below 1000 km. The discovery of negative ions in the ionosphere was also very exciting. A vigorous modeling effort aimed at explaining the structure and composition of the upper atmosphere and ionosphere is helping to put the data into a broader theoretical context. For example, solar extreme ultraviolet and x-ray radiation and energetic electrons from Saturn's magnetosphere interact with the upper atmosphere producing the ionosphere and initiating a complex neutral and ion chemistry that has important effects extending deep into the atmosphere.",
author = "Cravens, {T. E.} and Roger Yelle and Wahlund, {J. E.} and Shemansky, {D. E.} and Nagy, {A. F.}",
year = "2010",
doi = "10.1007/978-1-4020-9215-2_11",
language = "English (US)",
isbn = "9781402092145",
pages = "259--295",
booktitle = "Titan from Cassini-Huygens",
publisher = "Springer Netherlands",

}

TY - CHAP

T1 - Composition and structure of the ionosphere and thermosphere

AU - Cravens, T. E.

AU - Yelle, Roger

AU - Wahlund, J. E.

AU - Shemansky, D. E.

AU - Nagy, A. F.

PY - 2010

Y1 - 2010

N2 - Airglow emissions, radio and solar occultation data from the Voyager mission over a quarter of a century ago provided the main source of information on the composition and structure of Titan's upper atmosphere and ionosphere until October 2004, when the Cassini Orbiter first encountered Titan during the Ta fly-by. During this encounter, in situ measurements were made by many instruments onboard the Orbiter, including the Ion and Neutral Mass Spectrometer (INMS), the Radio Wave and Plasma Wave Spectrometer (RPWS), the Magnetometer (MAG), and the Cassini Plasma Spectrometer (CAPS). For example, INMS measurements confirmed that the major neutral species were molecular nitrogen and methane. Other species detected included mole cular hydrogen, acetylene, ethylene, benzene, and propane. The Langmuir probe part of the RPWS experiment observed substantial ionospheric electron densities and measured electron temperatures significantly exceeding the neutral temperature. A large set of data on the upper atmosphere and ionosphere has been collected during the many Titan encounters following Ta. The first composition measurements for the ionosphere were made by INMS during the outbound leg of the T5 pass in April 2005. A rich and complex ion-neutral chemistry scheme was predicted prior to the Cassini mission and the INMS composition data indeed revealed the presence of a very large number of ion species, both predicted and unpre-dicted. Stellar occultation measurements made by the Cassini Ultraviolet Spectrometer (UVIS) provided important information on the structure and composition of Titan's upper atmosphere, and radio occultation measurements made by the Radio Science Subsystem (RSS) revealed the existence of a substantial ionosphere even for altitudes below 1000 km. The discovery of negative ions in the ionosphere was also very exciting. A vigorous modeling effort aimed at explaining the structure and composition of the upper atmosphere and ionosphere is helping to put the data into a broader theoretical context. For example, solar extreme ultraviolet and x-ray radiation and energetic electrons from Saturn's magnetosphere interact with the upper atmosphere producing the ionosphere and initiating a complex neutral and ion chemistry that has important effects extending deep into the atmosphere.

AB - Airglow emissions, radio and solar occultation data from the Voyager mission over a quarter of a century ago provided the main source of information on the composition and structure of Titan's upper atmosphere and ionosphere until October 2004, when the Cassini Orbiter first encountered Titan during the Ta fly-by. During this encounter, in situ measurements were made by many instruments onboard the Orbiter, including the Ion and Neutral Mass Spectrometer (INMS), the Radio Wave and Plasma Wave Spectrometer (RPWS), the Magnetometer (MAG), and the Cassini Plasma Spectrometer (CAPS). For example, INMS measurements confirmed that the major neutral species were molecular nitrogen and methane. Other species detected included mole cular hydrogen, acetylene, ethylene, benzene, and propane. The Langmuir probe part of the RPWS experiment observed substantial ionospheric electron densities and measured electron temperatures significantly exceeding the neutral temperature. A large set of data on the upper atmosphere and ionosphere has been collected during the many Titan encounters following Ta. The first composition measurements for the ionosphere were made by INMS during the outbound leg of the T5 pass in April 2005. A rich and complex ion-neutral chemistry scheme was predicted prior to the Cassini mission and the INMS composition data indeed revealed the presence of a very large number of ion species, both predicted and unpre-dicted. Stellar occultation measurements made by the Cassini Ultraviolet Spectrometer (UVIS) provided important information on the structure and composition of Titan's upper atmosphere, and radio occultation measurements made by the Radio Science Subsystem (RSS) revealed the existence of a substantial ionosphere even for altitudes below 1000 km. The discovery of negative ions in the ionosphere was also very exciting. A vigorous modeling effort aimed at explaining the structure and composition of the upper atmosphere and ionosphere is helping to put the data into a broader theoretical context. For example, solar extreme ultraviolet and x-ray radiation and energetic electrons from Saturn's magnetosphere interact with the upper atmosphere producing the ionosphere and initiating a complex neutral and ion chemistry that has important effects extending deep into the atmosphere.

UR - http://www.scopus.com/inward/record.url?scp=84891401105&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84891401105&partnerID=8YFLogxK

U2 - 10.1007/978-1-4020-9215-2_11

DO - 10.1007/978-1-4020-9215-2_11

M3 - Chapter

AN - SCOPUS:84891401105

SN - 9781402092145

SP - 259

EP - 295

BT - Titan from Cassini-Huygens

PB - Springer Netherlands

ER -