Ionospheric photoelectrons: Comparing Venus, Earth, Mars and Titan

被引：62

作者：

Coates, A. J. ^{[1
,2
]}

Tsang, S. M. E. ^{[1
,2
]}

Wellbrock, A. ^{[1
,2
]}

Frahm, R. A. ^{[3
]}

Winningham, J. D. ^{[3
]}

Barabash, S. ^{[4
]}

Lundin, R. ^{[4
]}

Young, D. T. ^{[3
]}

Crary, F. J. ^{[3
]}

机构：

[1] Univ Coll London, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England

[2] UCL Birkbeck, Ctr Planetary Sci, London WC1E 6BT, England

[3] SW Res Inst, San Antonio, TX 78228 USA

[4] Swedish Inst Space Phys, S-98128 Kiruna, Sweden

来源：

PLANETARY AND SPACE SCIENCE | 2011年 / 59卷 / 10期

基金：

英国科学技术设施理事会;

关键词：

Earth; Venus; Mars; Titan; Ionosphere; Photoelectrons; CASSINI PLASMA SPECTROMETER; SOLAR MINIMUM CONDITIONS; AE-E MEASUREMENTS; ATMOSPHERE EXPLORER; DAYSIDE IONOSPHERE; ENERGY PEAKS; ION ESCAPE; FLUXES; MAGNETOSPHERE; ELECTRONS;

D O I：

10.1016/j.pss.2010.07.016

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

The sunlit portion of planetary ionospheres is sustained by photoionization. This was first confirmed using measurements and modelling at Earth, but recently the Mars Express, Venus Express and Cassini-Huygens missions have revealed the importance of this process at Mars, Venus and Titan, respectively. The primary neutral atmospheric constituents involved (O and CO2 in the case of Venus and Mars, O and N-2 in the case of Earth and N-2 in the case of Titan) are ionized at each object by EUV solar photons. This process produces photoelectrons with particular spectral characteristics. The electron spectrometers on Venus Express and Mars Express (part of ASPERA-3 and 4, respectively) were designed with excellent energy resolution (Delta E/E-8%) specifically in order to examine the photoelectron spectrum. In addition, the Cassini CAPS electron spectrometer at Saturn also has adequate resolution (Delta E/E=16.7%) to study this population at Titan. At Earth, photoelectrons are well established by in situ measurements, and are even seen in the magnetosphere at up to 7R(E). At Mars, photoelectrons are seen in situ in the ionosphere, but also in the tail at distances out to the Mars Express apoapsis (similar to 3R(M)). At both Venus and Titan, photoelectrons are seen in situ in the ionosphere and in the tail (at up to 1.45R(V) and 6.8R(T), respectively). Here, we compare photoelectron measurements at Earth, Venus, Mars and Titan, and in particular show examples of their observation at remote locations from their production point in the dayside ionosphere. This process is found to be common between magnetized and unmagnetized objects. We discuss the role of photoelectrons as tracers of the magnetic connection to the dayside ionosphere, and their possible role in enhancing ion escape. (C) 2010 Elsevier Ltd. All rights reserved.

引用

页码：1019 / 1027

页数：9

共 62 条

[1] On magnetospheric electron impact ionisation and dynamics in Titan's ram-side and polar ionosphere - a Cassini case study [J].

Agren, K. ;

Wahlund, J. -E. ;

Modolo, R. ;

Lummerzheim, D. ;

Galand, M. ;

Mueller-Wodarg, I. ;

Canu, P. ;

Kurth, W. S. ;

Cravens, T. E. ;

Yelle, R. V. ;

Waite, J. H., Jr. ;

Coates, A. J. ;

Lewis, G. R. ;

Young, D. T. ;

Bertucci, C. ;

Dougherty, M. K. .

ANNALES GEOPHYSICAE, 2007, 25 (11) :2359-2369

[2] On the ionospheric structure of Titan [J].

Agren, K. ;

Wahlund, J. -E. ;

Garnier, P. ;

Modolo, R. ;

Cui, J. ;

Galand, M. ;

Mueller-Wodarg, I. .

PLANETARY AND SPACE SCIENCE, 2009, 57 (14-15) :1821-1827

[3] Warping of Saturn's magnetospheric and magnetotail current sheets [J].

Arridge, C. S. ;

Khurana, K. K. ;

Russell, C. T. ;

Southwood, D. J. ;

Achilleos, N. ;

Dougherty, M. K. ;

Coates, A. J. ;

Leinweber, H. K. .

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, 2008, 113 (A8)

[4] The analyser of space plasmas and energetic atoms (ASPERA-4) for the Venus express mission [J].

Barabash, S. ;

Sauvaud, J.-A. ;

Gunell, H. ;

Andersson, H. ;

Grigoriev, A. ;

Brinkfeldt, K. ;

Holinstroem, M. ;

Lundin, R. ;

Yamauchi, M. ;

Asamura, K. ;

Baumjohann, W. ;

Zhang, T. L. ;

Coates, A. J. ;

Linder, D. R. ;

Kataria, D. O. ;

Curtis, C. C. ;

Hsieh, K. C. ;

Sandel, B. R. ;

Fedorov, A. ;

Mazelle, C. ;

Thocaven, J. J. ;

Grande, M. ;

Koskinen, Hannu E. J. ;

Kallio, E. ;

Saeles, T. ;

Riihela, P. ;

Kozyra, J. ;

Krupp, N. ;

Woch, J. ;

Luhmann, J. ;

McKenna-Lawlor, S. ;

Orsini, S. ;

Cerulli-Irelli, R. ;

Mura, M. ;

Milillo, M. ;

Maggi, M. ;

Roelof, E. ;

Brandt, P. ;

Russell, C. T. ;

Szego, K. ;

Winningham, J. D. ;

Frahm, R. A. ;

Scherrer, J. ;

Sharber, J. R. ;

Wurz, P. ;

Bochsler, P. .

PLANETARY AND SPACE SCIENCE, 2007, 55 (12) :1772-1792

[5] The analyzer of space plasmas and energetic atoms (ASPERA-3) for the mars express mission [J].

Barabash, S. ;

Lundin, R. ;

Andersson, H. ;

Brinkfeldt, K. ;

Grigoriev, A. ;

Gunell, H. ;

Holmstrom, M. ;

Yamauchi, M. ;

Asamura, K. ;

Bochsler, P. ;

Wurz, P. ;

Cerulli-Irelli, R. ;

Mura, A. ;

Milillo, A. ;

Maggi, M. ;

Orsini, S. ;

Coates, A. J. ;

Linder, D. R. ;

Kataria, D. O. ;

Curtis, C. C. ;

Hsieh, K. C. ;

Sandel, B. R. ;

Frahm, R. A. ;

Sharber, J. R. ;

Winningham, J. D. ;

Grande, M. ;

Kallio, E. ;

Koskinen, H. ;

Riihela, P. ;

Schmidt, W. ;

Sales, T. ;

Kozyra, J. U. ;

Krupp, N. ;

Woch, J. ;

Livi, S. ;

Luhmann, J. G. ;

McKenna-Lawlor, S. ;

Roelof, E. C. ;

Williams, D. J. ;

Sauvaud, J.-A. ;

Fedorov, A. ;

Thocaven, J.-J. .

SPACE SCIENCE REVIEWS, 2006, 126 (1-4) :113-164

[6] Ionospheric photoelectrons at Venus:: Initial observations by ASPERA-4 ELS [J].

Coates, A. J. ;

Frahm, R. A. ;

Linder, D. R. ;

Kataria, D. O. ;

Soobiah, Y. ;

Collinson, G. ;

Sharber, J. R. ;

Winningham, J. D. ;

Jeffers, S. J. ;

Barabash, S. ;

Sauvaud, J. -A. ;

Lundin, R. ;

Holmstrom, M. ;

Futaana, Y. ;

Yamauchi, M. ;

Grigoriev, A. ;

Andersson, H. ;

Gunell, H. ;

Fedorov, A. ;

Thocaven, J. -J. ;

Zhang, T. L. ;

Baumjohann, W. ;

Kallio, E. ;

Koskinen, H. ;

Kozyra, J. U. ;

Liemohn, M. W. ;

Ma, Y. ;

Galli, A. ;

Wurz, P. ;

Bochsler, P. ;

Brain, D. ;

Roelof, E. C. ;

Brandt, P. ;

Krupp, N. ;

Woch, J. ;

Fraenz, M. ;

Dubinin, E. ;

McKenna-Lawlor, S. ;

Orsini, S. ;

Cerulli-Irelli, R. ;

Mura, A. ;

Milillo, A. ;

Maggi, M. ;

Curtis, C. C. ;

Sandel, B. R. ;

Hsieh, K. C. ;

Szego, K. ;

Asamura, A. ;

Grande, M. .

PLANETARY AND SPACE SCIENCE, 2008, 56 (06) :802-806

[7] Ionospheric electrons in Titan's tail: Plasma structure during the cassini T9 encounter [J].

Coates, A. J. ;

Crary, F. J. ;

Young, D. T. ;

Szego, K. ;

Arridge, C. S. ;

Bebesi, Z. ;

Sittler, E. C., Jr. ;

Hartle, R. E. ;

Hill, T. W. .

GEOPHYSICAL RESEARCH LETTERS, 2007, 34 (24)

[8] IONOSPHERIC PHOTOELECTRONS OBSERVED IN THE MAGNETOSPHERE AT DISTANCES UP TO 7-EARTH RADII [J].

COATES, AJ ;

JOHNSTONE, AD ;

SOJKA, JJ ;

WRENN, GL .

PLANETARY AND SPACE SCIENCE, 1985, 33 (11) :1267-1275

[9] Plasma electrons above Saturn's main rings: CAPS observations [J].

Coates, AJ ;

McAndrews, HJ ;

Rymer, AM ;

Young, DT ;

Crary, FJ ;

Maurice, S ;

Johnson, RE ;

Baragiola, RA ;

Tokar, RL ;

Sittler, EC ;

Lewis, GR .

GEOPHYSICAL RESEARCH LETTERS, 2005, 32 (14) :1-4

[10] Interaction of Titan's ionosphere with Saturn's magnetosphere [J].

Coates, Andrew J. .

PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, 2009, 367 (1889) :773-788

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