Title page for 91229015


[Back to Results | New Search]

Student Number 91229015
Author Wei-Ling Tseng(歓浤)
Author's Email Address d939006@astro.ncu.edu.tw
Statistics This thesis had been viewed 1511 times. Download 621 times.
Department Graduate Institute of Astronomy
Year 2009
Semester 1
Degree Ph.D.
Type of Document Doctoral Dissertation
Language English
Title The Structure and Dynamics of the Neutral Cloud in the Saturnian System
Date of Defense 2009-10-14
Page Count 107
Keyword
  • exosphere
  • magnetosphere
  • plasma
  • rings
  • Saturn
  • Titan
  • Abstract From HST observations, Voyager flyby measurements and the Cassini in-situ measurements, we have learned that the Saturnian system is immersed in a vast neutral gas cloud of oxygen molecules, water molecules and their photodissociative products like OH, O and H. Most of the gas molecules originate from the plumes in the south pole of Enceladus plus some small contribution from other inner icy satellites. In addition, the ring system is an important source of oxygen atoms and molecules which can be injected into the distant Saturnian magnetosphere via scattering processes. Titan・s exosphere is another major source contributing neutral gas like H2 and H, and probably also CH4 and N2. These neutral materials will be fed into the thermal plasma disk in the inner Saturnian magnetosphere. In this work, the model calculations have been performed to simulate the structures and compositions of the neutral gas clouds of different origins making use of an updated photochemical and plasma chemistry model based on the latest plasma measurements from Cassini CAPS instrument.
    The present modeling efforts have first led to the picture that an exospheric population of neutral oxygen molecules can be maintained in the vicinity of the main rings by means of photolytic decomposition of ice and other surface reactions. The momentum exchange effect via charge exchange collisions has been taken into consideration in the computation. The ring atmosphere, therefore, serves as a source of O2+ ions throughout Saturn・s magnetosphere. By the same token, our results also show that the magnetopheric O2+ ions should be nearly depleted at Saturn・s equinox if O2 is produced mainly by photolysis of the ring material.
    Secondly, we have examined the mass budget of the ring oxygen atmosphere of Saturn taking into account of the possibility of an :exogenic; source i.e. Enceladus・ neutral gas cloud. The maximum O2 source rate from recycling of Enceladus-originated plasma and neutrals might be comparable to the maximum value from photolytic decomposition of the icy ring particles. In this case, the neutral O2 source rate in the Saturnian magnetosphere would be independent of the solar insolation angle. It is also shown that the O2 source from other inner icy satellites is smaller comparable to the scattered O2 component of ring-origin.
    The third part of our work is about Titan・s exospheric interaction with the corotating magnetospheric plasma. From the Cassini observations, we know that the magnetic field configuration and plasma flow field are highly variable. We have employed the numerical results of the three dimensional MHD simulation of Kopp and Ip (2001) to study possible spatial and temporal variations in the pickup ion influx. The computation of the ion influx and energy deposit into Titan・s exobase for the H2+, CH4+ and N2+ pickup ions separately are shown. The model results of four different Titan・s orbital locations are also presented.
    Finally, we consider the distribution of hydrogen atoms escaping from Titan due to the long-term perturbation effects of the solar radiation pressure and planetary oblateness as Saturn orbits Sun.
    Table of Content Table of Contents
    Chapter 1: Research Background KKKKKKKKKKKKKKKK...1
    1.1 Research goals and outline KKKKKKKKKKKKKKKKKKKKK...1
    Chapter 2: Introduction KKKKKKKKKKKKKKKKKKKK..4
    2.1Saturnian system overview KKKKKKKKKKKKKKKK..4
    2.1.1Saturn and its ring system KKKKKKKKKKKKKKKKK....4
    2.1.2Enceladus and other inner icy satellites KKKKKKKKKKKK...7
    2.1.3Titan KKKKKKKKKKKKKKKKKKKKKKKKKK.8
    2.1.4Magnetosphere and its plasma interaction with the satellites KKK....10
    2.2The neutral cloud environment in the Saturnian system KKKKKKKKK....13
    2.2.1Previous observations and modeling of the neutral clouds. K..KKK.13
    2.3Cassini-Huygens Mission Overview KKKKKKKKKKKKKKKKK..15
    2.3.1  Mission descriptions K..KKKKKKKKKKKKKKKKKK15
    2.3.2Instrument descriptions KKKKKKKKKKKKKKKKKK..16
    Chapter 3: The Structure and Time Variability of the Ring Atmosphere and Ionosphere KKKKKKKKKKKKKKKKKKKKKKK....17
    3.1Introduction .KKKKKKKKKKKKKKKKKKKKKKKKKK...17
    3.2Modeling descriptions KKKKKKKKKKKKKKKKKKKKKKK20
    3.2.1A model of neutral O2 atmosphere KKKKKKKKKKKKK.....20
    3.2.2Ion production and transport KKKKKKKKKKKKKKKK..23
    3.2.3Ion molecule charge exchange collisions KK.KKKKKKKKK..24
    3.3Saturn Orbit Insertion conditions KKKKKKKKKKKKKKKK.KK..28
    3.4Seasonal variations KKKKKKKKKKKKKKKKKKKKK.KKK31
    3.5Discussions KKKKKKKKKKKKKKKKKKKKKKKK.KKK31
    Chapter 4: An Assessment and Test of Enceladus as an Important Source of Saturn・s Ring Atmosphere and Ionosphere KKKKKKKKKK..42
    4.1Introduction KKKKKKKKKKKKKKKKKKKKKKKKKK....42
    4.2Model Calculations KKKKKKKKKKKKKKKKKKKKKKKK45
    4.2.1Test particle model of ring O2 atmosphere and O2+ ionosphere ..KKK.45
    4.2.2Mass transfer from Enceladus・ plume material KKKKKKKKK.46
    4.3Results KKKKKKKKKKKKKKKKKKKKKKKKKKKK....47
    4.3.1Exploration of the Enceladus-related source of O2 in three cases in SOI and Equinox KKKKKKKKKKKKKKKKKKKKKK...47
    4.4Discussions KKKKKKKKKKKKKKKKKKKKKKKKKKK50
    Chapter 5: Exospheric Heating by Pickup Ions at Titan KKKKKKK55
    5.1Introduction KKKKKKKKKKKKKKKKKKKKKKKKKKK55
    5.2Model description: MHD model and test particle model KKKKKKKKK...57
    5.3Results KKKKKKKKKKKKKKKKKKKKKKKKKKKKK59
    5.3.1Energy flux distribution of the H2+, CH4+ and N2+ pickup ions at Titan in four different orbital configurations KKKKKKKKKKKK...60
    5.4Discussions KKKKKKKKKKKKKKKKKKKKKKKKKKK.61
    Chapter 6: The Distribution of the Atomic Hydrogen in the Saturnian System KKKKKKKKKKKKKKKKKKKKKKKKK...69
    6.1Introduction KKKKKKKKKKKKKKKKKKKKKKKKKKK69
    6.2Model description: orbital integration and a plasma chemistry network KKK...71
      6.3Results KKKKKKKKKKKKKKKKKKKKKKKKKKKKK74
      6.4Discussions KKKKKKKKKKKKKKKKKKKKKKKKKKK.76
    Chapter 7: Summary KKKKKKKKKKKKKKKKKKKKK..81
    References KKKKKKKKKKKKKKKKKKKKKKKKK...84
    Appendix A: Published Articles KKKKKKKKKKKKKKKKK..92
    List of Figures
    Figure 2.1: Image of Saturn and its prominent rings taken by CassiniKKKKKKKKK....6
    Figure 2.2: The Saturn・s satellites and ring structureKKKKKKKKKKKKKKKK..6
    Figure 2.3: Image of Enceladus・ plumes taken by CassiniKKKKKKKKKKKKKK..6
    Figure 2.4: The appearances of Titan in three wavelengthsKKKKKKKKKKKKK..10
    Figure 2.5: Image of the lakes on Titan・s surface taken by Cassini RadarKKKKKKK...10
    Figure 2.6: The structure of Saturn・s magnetosphereKKKKKKKKKKKKKKKK12
    Figure 2.7: Illustration of Titan・s interaction with Saturn・s magnetospheric plasmaKKKK12
    Figure 2.8: The major sources of neutral clouds in the Saturnian systemKKKKKKKK.13
    Figure 3.1a: The flow chart of the Monte Carlo procedure on the trajectory calculation of neutral O2KKKKKKKKKKKKKKKKKKKKKKKKKKKKKK...26
    Figure 3.1b: The flow chart of the Monte Carlo procedure on the trajectory calculation of O2+ ionsKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKK.27
    Figure 3.2: The trajectories of the O2+ ion motion in different radial distances from SaturnK35
    Figure 3.3a: The neutral O2 number densityKKKKKKKKKKKKKKKKKKK..35
    Figure 3.3b: The O2 column density with variation of radial distance KKKKKKKKK.36
    Figure 3.3c: The O2 number density along the Z-direction in the different radial distancesK.36
    Figure 3.3d: The neutral O2 scale height in the radial distances in the equatorial plane ...K...37
    Figure 3.4a: The O2+ ion number density in Log10 scaleKKKKKKKKKKKKKK...37
    Figure 3.4b: The O2+ ion number density at 0.01 RS below and above the ring planeKKK..38
    Figure 3.4c: The O2+ ion column density above the ring plane and below the ring planeKK.38
    Figure 3.5a: The neutral O2 column density (molecules/cm2) in four situationsKKKKK...39
    Figure 3.5b: The O2+ ion density for the solar incident angle ~24X south of the ring plane (top-left), ~24X north of the ring plane (top-right), ~14X north of the ring plane (bottom-left), ~4X north of the ring plane (bottom-right)KKKKKKKKKKKK...40
    Figure 3.6: The Saturn atmospheric impact rates and the magnetospheric injection rates with variations of solar incident anglesKKKKKKKKKKKKKKKKKKKKK..41
    Figure 4.1: The O2+ ion distributions in SOI phase (QP~1026 s-1). (a) Total source rate = 1.1}1026 s-1 (b) Total source rate = 2.0}1026 s-1 (c) Total source rate = 1.1}1027 s-1KK.52
    Figure 4.2: The O2+ ion distributions in Equinox phase (QP~1025 s-1). (a) Total source rate = 2.0}1025 s-1 (b) Total source rate = 1.1}1026 s-1 (c) Total source rate = 1.01}1027 s-1K...53
    Figure 4.3a: The radial distribution of the neutral O2 column densities in 3 cases in SOI phase: total source rate ~1.1}1026 s-1, total source rate ~2.0}1026 s-1, and total source rate ~1.1}1027 s-1KKKKKKKKKKKKKKKKKKKKKKKKKKKKK...54
    Figure 4.3b: The radial distribution of the neutral O2 column densities in 3 cases in Equinox phase: total source rate ~2.0}1025 s-1, total source rate ~1.1}1026 s-1, and total source rate ~1.0}1027 s-1KKKKKKKKKKKKKKKKKKKKKKKKKKKKK...54
    Figure 5.1: The trajectories of the H2+, CH4+ and N2+ pickup ion projected on the xVy plane in the unit of Titan・s radiusKKKKKKKKKKKKKKKKKKKKKKKKK64
    Figure 5.2: The orientations of the dayside ionosphere of Titan with respect to the direction of the corotating plasma flow at four different orbital phases (SL = 0, 6, 12, and 18)KK..64
    Figure 5.3: The log of the energy influx (eV/m2 s-1) deposit on Titan・s exobaseKKKKK..65
    Figure 5.4: The log of the energy influx (eV/m2 s-1) of N2+ pickup ions deposit on Titan・s exobase in four different Saturn local time (SL)KKKKKKKKKKKKKKKK66
    Figure 5.5: The log of the energy influx (eV/m2 s-1) of CH4+ pickup ions deposit on Titan・s exobase in four different Saturn local time (SL)KKKKKKKKKKKKKKKK67
    Figure 5.6: The log of the energy influx (eV/m2 s-1) of H2+ pickup ions deposit on Titan・s exobase in four different Saturn local time (SL)KKKKKKKKKKKKKKKK68
    Figure 6.1a: The initial condition for the geometry of the coordinate system: inlination angle=25X (SOI phase) and the orbital phase angle X=0XKKKKKKKKKKKK.73
    Figure 6.1b: The initial condition for the geometry of the coordinate system: inlination angle=0X (Equinox phase) and the orbital phase angle X=90XKKKKKKKKKK..73
    Figure 6.2: The column density of Titan・s atomic hydrogen torus on the equatorial plane in case of SOI (right) and Equinox (left)KKKKKKKKKKKKKKKKKKK...77
    Figure 6.3a: The number density of the hydrogen torus in the vertical view (R-Z direction) along the line of Midnight-Noon in case of SOI (upper) and Equinox (bottom)KKK..77
    Figure 6.3b: The number density of the hydrogen torus in the vertical view (R-Z direction) along the line of Dusk-Dawn in case of SOI (upper) and Equinox (bottom)KKKK....78
    Figure 6.4a: Probabiliy distributions of H knetic energy of electron impact rectionsKKK...78
    Figure 6.4b: The probability distribution of the accumulative energy of the hydrogen atoms suffering the mutual collisions with the ambient H2 at 1 scale height above the exobase.79
    Figure 6.5: The column density of Saturn hydrogen plume on the equatorial plane.................80
    Figure 6.6: The number density of Saturn hydrogen plume in the vertical view (R-Z direction) along the line of Midnight-NoonKKKKKKKKKKKKKKKKKKKKK...81
    List of Tables
    Table 4.1: The atmospheric precipitation rates and magnetospheric injection rates of O2 for all three different cases under SOI phase and Equinox phaseKKKKKKKKKKKK51
    Table 5.1: The total ion impact flux (ions/s) into Titan・s exobaseKKKKKKKKKKK63
    Table 5.2: The Total energy deposit rates (eV/s) into Titan・s exobaseKKKKKKKKK.63
    Reference 1.Barbosa, D.D. (1987),Titan・s atomic nitrogen torus: inferred properties and consequences for the Saturnian aurora. Icarus 72, 53V61.
    2.Bouhram, M.; R. E. Johnson; J.-J. Berthelier; J.-M. Illiano; R. L. Tokar; D. T. Young; F. J. Crary (2006), A test-particle model of the atmosphere/ionosphere system of Saturn's main rings, Geophys. Res. Lett., 33, L05016.
    3.Burger, M. H., E. C. Sittler Jr., R. E. Johnson, H. T. Smith, O. J. Tucker and V. I. Shematovich (2007), Understanding the escape of water from Enceladus, J. Geophys. Res., 112, J. Geophys. Res., A06219
    4.Bridge, H. S.; J. W. Belcher; A. J. Lazarus et al., (1981), Plasma observations near Saturn - Initial results from Voyager 1, Science, 212, 217-224.
    5.Bridge, H. S.; F. Bagenal; J. W. Belcher et al., (1982), Plasma observations near Saturn - Initial results from Voyager 2, Science, 215, 563-570.
    6.Broadfoot, A. L.; Sandel, B. R.; Shemansky, D. E.; Holberg, J. B.; Smith, G. R.; Strobel, D. F.; McConnell, J. C.; Kumar, S.; Hunten, D. M.; Atreya, S. K.; Donahue, T. M.; Moos, H. W.; Bertaux, J. L.; Blamont, J. E.; Pomphrey, R. B.; Linick, S. (1981), Extreme ultraviolet observations from Voyager 1 encounter with Saturn, Science, 212, 206-211
    7.Carlson, R. W. (1980), Photosputtering of Saturn・s rings, Nature, 283, 461-463.
    8.Chambers, L. S., J. N. Cuzzi, E. Asphaug, J. Colwell, S. Sugita (2008), Hydrodynamical and radiative transfer modeling of meteoroid impacts into Saturn・s rings, Icarus, 194, 623-635.
    9.Coates , A. J.; H. J. McAndrews, A. M. Rymer, D. T. Young, F. J. Crary, S. Maurice, R. E. Johnson (2005), Plasma electrons above Saturn's main rings: CAPS observations, Geophys. Res. Lett., 32, L14S09
    10.Connerney, J. E. P., M. H. Acuna, F. N. Ness (1983), Currents in Saturn's magnetosphere, J. Geophys. Res., 88, 8779-8789.
    11.Connerney, J. E. P., and J. H. Waite (1984), New model of Saturn・s ionosphere with an influx of water from the rings, Nature, 312, 136-138.
    12.Cui, J.; Yelle, R. V.; Volk, K (2008), Distribution and escape of molecular hydrogen in Titan's thermosphere and exosphere, J. Geophys. Res., 113, E10004
    13.Cravens, T.E., Vann, J., Clark, J., Yu, J., Keller, C.N., Brull, C. (2004),The ionosphere of Titan: an updated theoretical model. Adv. Space Res. 33, 212V215.
    14.Farrell, W. M.; M. L. Kaiser; D. A. Gurnett; W. S. Kurth; A. M. Persoon; J. E. Wahlund; P. Canu (2008), Mass unloading along the inner edge of the Enceladus plasma torus, Geophys. Res. Lett., 35, L02203
    15.de Graauw, T.; H. Feuchtgruber; B. Bezard et al. (1997), First results of ISO-SWS observations of Saturn: detection of CO2, CH3C2H, C4H2 and tropospheric H2O, A&A, 321, L13-L16
    16.Esposito, L. W., M. Ocallaghan, K. E. Simmons, C. W. Hord, R. A. West, A. L. Lane, R. B. Pomphrey, D. L. Coffeen and M. Sato (1983), Voyager photopolarimeter stellar occultation of Saturn・s rings, J. Geophys. Res., 88, 8643-8649.
    17.Farrell,W. M.; M. L. Kaiser; D. A. Gurnett; W. S. Kurth; A. M. Persoon; J. E. Wahlund; P. Canu (2008), Mass unloading along the inner edge of the Enceladus plasma torus, Geophys. Res. Lett., 35, L02203
    18.Feuchtgruber, H.; E. Lellouch; T. de Graauw; B. Bezard; T. Encrenaz; M. Griffin (1997), External supply of oxygen to the atmospheres of giant planets ,Nature, 389, 159-162 Goertz, C. K., M. Morfill (1983), A model for the formation of spokes in Saturn's rings, Icarus,53,219-229
    19.Galand, M.L., Lilensten, J., Toublanc, D., Maurice, S. (1999), The ionosphere of Titan: ideal diurnal and noctunal cases. Icarus 140, 92V105.
    20.Goldreich, P. and A. J. Farmer (2007), Spontaneous axisymmetry breaking of the external magnetic field at Saturn, J. Geophys, Res. 112, A05225
    21.Graps, A.L., G. H. Jones, A. Juhasz, M. Horanyi, and O. Havnes (2008), The charging of planetary rings, Space Sci. Rev. 137, 435-453.
    22.Hansen, C. J.; L. Esposito; A. I. Stewart et al. (2006), Enceladus・ Water Vapor Plume, Science, 311, 1422-1425
    23.Hartle, R.E., Sittler Jr., E.C., Neubauer, F.M., Johnson, R.E., Smith, H.T., Crary, F., McComas, D.J., Young, D.T., Coates, A.J., Simpson, D., Bolton, S., Reisenfeld, D., Szego, K., Berthelier, J.J., Rymer, A., Vilppola, J., Andre, N. (2006), Preliminary interpretation of Titan plasma interaction as observed by the Cassini plasma spectrometer: comparisons with Voyager 1. Geophys. Res. Lett. 33.
    24.de La Haye, V., Waite, J.H., Cravens, T.E., Nagy, A.F., Johnson, R.E., Lebonnois, S., Robertson, I.P. (2007), Titan・s corona: the contribution of exothermic chemistry. Icarus 191, 236V250.
    25.de La Haye, V.; Waite, J. H.; Johnson, R. E.; Yelle, R. V.; Cravens, T. E.; Luhmann, J. G.; Kasprzak, W. T.; Gell, D. A.; Magee, B.; Leblanc, F.; Michael, M.; Jurac, S.;   Robertson, I. P. (2007), Cassini Ion and Neutral Mass Spectrometer data in Titan's upper atmosphere and exosphere: Observation of a suprathermal corona, J. Geophys. Res., 112, A07309
    26.Huebner, W.F., Giguere, P.T. (1980), A model of comet comae. II: Effects of solar photodissociation ionization. Astrophys. J. 238, 753.
    27.Huebner, W. F.; J. J. Keady; S. P. Lyon (1992), Solar photo rates for planetary atmospheres and atmospheric pollutants, Ap&SS, 195, 1-295
    28.Ip, W.-H. (1984a), Plasmatization and recondensation of the Saturnian rings, Nature, 320, 143-145.
    29.Ip, W.-H. (1984b), Electrostatic charging of the rings of Saturn: A parameter study, J. Geophys. Res.,89, 3829-3836.
    30.Ip, W.-H. (1984c), On the Equatorial Confinement of Thermal Plasma Generrated in Vicinity of the Rings of Saturn J. Geophys. Res., 89, 395-398.
    31.Ip, W.-H. (1988), On a hot oxygen corona of Mars, Icarus, 76, 135-145
    32.Ip, W.-H. (1995), Exospheric systems of Saturn・s rings, Icarus, 115, 295-303
    33.Ip, W.-H. (1996), The Asymmetric Distribution of Titan's Atomic Hydrogen Cloud as a Function of Local Time, ApJ, 457, 922
    34.Ip, W.-H. (1997), On the Neutral Cloud Distribution in the Saturnian Magnetosphere, Icarus, 126, 42-57
    35.Ip, W.-H. (2000), Thermal plasma composition in Saturn's magnetosphere, P&SS, 48, 7-8, 775-783
    36.Ip, W.-H. (2005), An update on the ring exosphere and plasma disc of Saturn, Geophys. Res. Lett., 32 L13204
    37.Johnson, R. E.; J. W. Boring; C. T. Reimann; L. A. Barton; J. W. Sieveka; J. W. Garrett; K. R. Farmer; W. L. Brown; L. J. Lanzerotti (1983), Plasma ion-induced molecular ejection on the Galilean satellites - Energies of ejected molecules, Geophys. Res. Lett., 10, 892-895
    38.Johnson, R.E. and T.I. Quickenden, (1997) :Photolysis and Radiolysis of Water Ice on Outer Solar System Bodies;, J. Geophys. Res.102, 10985-10996
    39.Johnson, R. E.; Liu, M.; Sittler, E. C. (2005), Plasma-induced clearing and redistribution of material embedded in planetary magnetospheres, Geophys. Res. Lett., 32 L24201
    40.Johnson, R.E., J.G. Luhmann, R.L. Tokar, M. Bouhram, J.J. Berthelier, E.C. Sittler, J.F.Cooper, T.W. Hill, F.J. Crary, and D.T. Young (2006), Production, ionization and redistribution of Saturn・s O2 ring atmosphere, Icarus, 180, 393-402.
    41.Jurac, S and J. D. Richardson (2005), A self-consistent model of plasma and neutrals at Saturn: Neutral cloud morphology, Geophys. Res. Lett., 110 A09220
    42.Jurac, S and J. D. Richardson (2007), Neutral cloud interaction with Saturn's main rings, Geophys. Res. Lett., 34 L08102
    43.Kabin, K., Gombosi, T.I., DeZeeuw, D.L., Powell, K.G., Israelevich, P.L. (1999), Interaction of the Saturnian magnetosphere with Titan. J. Geophys. Res. 104, 2451.
    44.Kabin, K., Israelevich, P.L., Ershkovich, A.I., Neubauer, F.M., Gombosi, T.I., DeZeeuw, D.L., Powell, K.G. (2000), Titan・s magnetic wake: atmospheric or magnetospheric interaction. J. Geophys. Res. 105 (10), 761.
    45.Kallio, E., Sillanpaa, I., Janhunen, P. (2004), Titan in subsonic and supersonic flow. Geophys. Res. Lett. 31, L15703.
    46.Kopp, A. (1996), Modifications of the electrodynamic interaction between Jupiter and Io due to mass loading effects. J. Geophys. Res. 101, 24943V24954.
    47.Kopp, A., Ip, W.-H. (2001), Asymmetric mass loading effect at Titan・s ionosphere. J. Geophys. Res. 106, 8323V8332.
    48.Krasnopolsky, Vladimir A. (2009), A photochemical model of Titan's atmosphere and ionosphere, Icarus, 201, 226-256
    49.Krimigis, S.M., Mitchell, D.G., Hamilton, D.C. et al. (2006), Dynamics of Saturn's Magnetosphere from MIMI During Cassini's Orbital Insertion, Science, 307, 1270-1273.
    50.Lammer, H., Bauer, S.J. (1993), Atmospheric mass loss from Titan by sputtering. Planet. Space Sci. 41, 657V663.
    51.Ledvina, S.A., Cravens, T.E. (1998), A three-dimensional MHD model of plasma flow around Titan. Planet. Space Sci. 46, 1175.
    52.Ledvina, S.A., Cravens, T.E. (2005), Ion distributions in Saturn・s magnetosphere near Titan. J. Geophys. Res. 110.
    53.Luhmann, J.G. (1996), Titan・s ion exosphere wake: a neutral ion mass spectrometer? J. Geophys. Res. 101, 29387V29393.
    54.Luhmann, J.G., R.E. Johnson, R.L. Tokar, Ledvina, S.A. and T.E. Cravens (2006), A model of the ionosphere of Saturn・s rings and its implications, Icarus, 181, 465-474.
    55.Ma, Yingjuan, Nagy, Andrew F., Cravens, Thomas E., et al. (2006), Comparisons between MHD model calculations and observations of Cassini flybys of Titan. J. Geophys. Res. 111, A05207.
    56.Martens, H.R., D.B. Reisenfeld, J.D. Williams, R.E. Johnson and H.T. Smith (2008), Observations of molecular oxygen ions in Saturn・s inner magnetosphere, Geophys. Res. Lett., 35 L20103.
    57.Melin, H.; D. E. Shemansky and X. Liu (2009), The distribution of atomic hydrogen and oxygen in the magnetosphere of Saturn, Planet. Space Sci., In press
    58.Michael, M., Johnson, R.E. (2005), Energy deposition of pickup ions and heating of Titan・s atmosphere. Planet. Space Sci. 53, 1510V1514.
    59.Michael, M., Johnson, R.E., Leblanc, F., Liu, M., Luhmann, J.G., Shematovich, V.I. (2005), Ejection of nitrogen from Titan・s atmosphere by magnetospheric ions and pick-up ions. Icarus 175, 263V267.
    60.Moore, L. E.; Mendillo, M.; Müller-Wodarg, I. C. F.; Murr, D. L. (2004), Modeling of global variations and ring shadowing in Saturn's ionosphere, Icarus, 172, 503-520
    61.Morfill, G. E., Fechtig, H., Grun, E., Goertz, C.K. (1983), Some consequences of meteoroid impacts on Saturn・s rings, Icarus 55, 439-447
    62.Moses, J.I., E. Lellouch, B. Bézard, G.R. Gladstone, H. Feuchtgruber and M. Allen (2000) Photochemistry of Saturn's Atmosphere. II. Effects of an Influx of External Oxygen, Icarus, 145, 166-202.
    63.Müller-Wodarg, I. C. F.; Yelle, R. V.; Cui, J.; Waite, J. H. (2008), Horizontal structures and dynamics of Titan's thermosphere, J. Geophys. Res. 113, E10005
    64.Nagy, A.F., Liu, Y., Hansen, K.C., Kabin, K., Gombosi, T.I., Combi, M.R., DeZeeuw, D.L., et al. (2001), The interaction between the magnetosphere of Saturn and Titan・s ionosphere. J. Geophys. Res. 106, 6151V6160.
    65.Ness, N.F., Acuna, M.H., Behannon, K.W., Neubauer, F.M. (1982), The induced magnetosphere of Titan. J. Geophys. Res. 87, 1369V1381.
    66.Neubauer, F.M., Gurnett, D.A., Scudder, J.D., Hartle, R.E. Titan・s magnetospheric interaction, in: Gehrels, T., Matthews, M.S. (1984), (Eds.), Saturn. University of Arizona Press, Tucson, pp. 760V787.
    67.Otto, A. (1990), 3D resistive MHD computations of magnetospheric physics. Comput. Phys. Commun. 59, 185V195.
    68.Porco, C. C.; P. Helfenstein; P. C. Thomas et al., (2006), Cassini Observes the Active South Pole of Enceladus, Science, 311, 1393-1401
    69.Pospieszalska, M.K. and R.E. Johnson (1991), Micrometeorite erosion of the main rings as a source of plasma in the inner Saturnian plasma torus. Icarus, 93, 45-52
    70.Richardson, J. D. and E.C. Sittler (1990), A plasma density model for Saturn based on Voyager observations, J. Geophys. Res.95, 12019-12031
    71.Richardson, John D. (1995), An extended plasma model for Saturn, Geophys. Res. Lett., 22, 1177-1180
    72.Shemansky, D. E. and T. D. Hall (1992), The distribution of atomic hydrogen in the magnetosphere of Saturn, J. Geophys. Res.97,4143-4161
    73.Shemansky, D. E.; P. Matheson; T. D. Hall; H.-Y. Hu; T. M. Tripp (1993), Detection of the hydroxyl radical in the Saturn magnetosphere, Nature, 363, 329-331
    74.Shemansky, D. E.; X, Liu and H. Melin (2009), The Saturn hydrogen plume, Planet. Space Sci., In press
    75.Sillanpaa, I., Kallio, E., Janhunen, P., Schmidt, W., Mursula, K., Vilppola, J., Tanskanen, P. (2006), Hybrid simulation study of ion escape at Titan for different orbital positions. Adv. Space Res. 38, 799V805.
    76.Sittler, E.C., Johnson, R.E., Jurac, S., Richardson, J.D., McGrath, M., Crary, F., Young, D.T., Nordholt, J.E. (2004), Pickup ions at Dione and Enceladus: Cassini plasma spectrometer simulations. J. Geophys. Res. 109, A01214.
    77.Sittler Jr., E.C., Hartle, R.E., Vinas, A.F., Johnson, R.E., Smith, H.T., Mueller-Wodarg, I. (2005), Titan interaction with Saturn・s magnetosphere: Voyager 1 results revisited. J. Geophys. Res. 110.
    78.Smith, H.T., Johnson, R.E., Shematovich, V. (2004), Titan・s atomic and molecular nitrogen tori. Geophys. Res. Lett. 31, L16804.
    79.Smyth, W. H.; Marconi, M. L. (1993), The nature of the hydrogen tori of Titan and Triton, Icarus, 101, 18-32
    80.Strobel Darrell F. (2008), Titan's hydrodynamically escaping atmosphere, Icarus, 193, 588-594
    81.Tokar et al., (2005), Cassini observations of the thermal plasma in the vicinity of Saturn・s main ring and the F and G rings, Geophys. Res. Lett., 32 L14S04
    82.Tseng, Wei-Ling, W.-H. Ip, R. E. Johnson, T. A. Cassidy and M. K. Erlod (2009), The Structure and Time Variability of the Ring Atmosphere and Ionosphere, Icarus, In press.
    83.Waite, J. H., et al. (2005), Oxygen ions observed near Saturn・s A ring, Science, 307, 1260-1262
    84.Waite, J.H., Niemann, H., Yelle, R., et al. (2005), Ion neutral mass spectrometer results from the first flyby of Titan. Science 308, 982V986.
    85.Waite, J. H; M. R. Combi; W.-H. Ip et al., (2006), Cassini Ion and Neutral Mass Spectrometer: Enceladus Plume Composition and Structure, Science, 311, 1419-1422
    86.Westley, M., R.A. Baragiola, R.E. Johnson, and G. Baratta (1995) Photo desorption from low temperature water ice: Astrophysical Implications, Nature 373, 405-407.
    87.Yelle, Roger V.; Borggren, N.; de La Haye, V.; Kasprzak, W. T.; Niemann, H. B.; Müller-Wodarg, I.; Waite, J. H. (2006), The vertical structure of Titan's upper atmosphere from Cassini Ion Neutral Mass Spectrometer measurements, Icarus, 182, 567-576
    88.Yelle, R. V.; Cui, J.; Müller-Wodarg, I. C. F. (2008), Methane escape from Titan's atmosphere, J. Geophys. Res., 113, E10003
    89.Young, D. T., et al. (2005), Composition and dynamics of plasma in Saturn・s magnetosphere, Science, 307,1262-1266.
    Advisor
  • Wing-Huen Ip(賢ッj)
  • Files
  • 91229015.pdf
  • approve in 1 year
    Date of Submission 2009-10-19

    [Back to Results | New Search]


    Browse | Search All Available ETDs

    If you have dissertation-related questions, please contact with the NCU library extension service section.
    Our service phone is (03)422-7151 Ext. 57407,E-mail is also welcomed.