MESSENGER and Mariner 10 Flyby Observations of Magnetotail Structure and Dynamics at Mercury

increasing antisunward distance ∣X∣, B � ∣X∣ G , with G varying from � 5.4 for northward to � 1.6 for southward IMF. Low-latitude boundary layers (LLBLs) containing strong northward magnetic field were detected at the tail flanks during two of the flybys. The observed thickness of the LLBL was � 33% and 16% of the radius of the tail during M1 and M3, respectively, but the boundary layer was completely absent during M2. Clear signatures of tail reconnection are evident in the M2 and M3 magnetic field measurements. Plasmoids and traveling compression regions were observed during M2 and M3 with typical durations of � 1–3 s, suggesting diameters of � 500–1500 km. Overall, the response of Mercury’s magnetotail to the steady southward IMF during M2 appeared very similar to steady magnetospheric convection events at Earth, which are believed to be driven by quasi-continuous reconnection. In contrast, the M3 measurements are dominated by tail loading and unloading events that resemble the large-scale magnetic field reconfigurations observed during magnetospheric substorms at Earth.

[1]  D. L. De Zeeuw,et al.  Multi-Scale Modeling of Magnetospheric Reconnection. , 2007 .

[2]  A. Lagg,et al.  Mass release process in the Jovian magnetosphere: Statistics on particle burst parameters , 2008 .

[3]  Kenneth G. Powell,et al.  Interaction of Mercury with the Solar Wind , 1998 .

[4]  Christopher T. Russell,et al.  An extended study of the low‐latitude boundary layer on the dawn and dusk flanks of the magnetosphere , 1987 .

[5]  E. W. Hones,et al.  ISEE 3 observations of traveling compression regions in the Earth`s magnetotail , 1993 .

[6]  S. Solomon,et al.  Modeling of the magnetosphere of Mercury at the time of the first MESSENGER flyby , 2010 .

[7]  J. Slavin,et al.  Alfven Wave Reflection model of field-aligned currents at Mercury , 2010 .

[8]  B. Anderson,et al.  Mercury’s magnetosphere–solar wind interaction for northward and southward interplanetary magnetic field: Hybrid simulation results , 2010 .

[9]  W. Hughes,et al.  On the formation and evolution of plasmoids: A survey of ISEE 3 geotail data , 1992 .

[10]  S. Solomon Department of terrestrial magnetism , 2000 .

[11]  K. Schindler,et al.  A theory of the substorm mechanism , 1974 .

[12]  J. Dungey Interplanetary Magnetic Field and the Auroral Zones , 1961 .

[13]  S. Solomon,et al.  MESSENGER observations of large flux transfer events at Mercury , 2010 .

[14]  C. Kennel,et al.  CHANGES IN MAGNETOSPHERIC CONFIGURATION DURING SUBSTORM GROWTH PHASE. , 1972 .

[15]  A. Otto,et al.  Kelvin Helmholtz Instability at the Equatorial Magnetotail Boundary: Mhd Simulation and Comparison with Geotail Observations , 2013 .

[16]  G. Siscoe,et al.  Open Geospace General Circulation Model simulation of a substorm: Axial tail instability and ballooning mode preceding substorm onset , 2010 .

[17]  L. Nittler,et al.  Observations of suprathermal electrons in Mercury's magnetosphere during the three MESSENGER flybys , 2010 .

[18]  Joachim Raeder,et al.  The structure of the distant geomagnetic tail during long periods of northward IMF , 1995 .

[19]  D. Fairfield On the average configuraton of the geomagnetic tail , 1979 .

[20]  D. Baker,et al.  Electron transport and precipitation at Mercury during the MESSENGER flybys: Implications for electron-stimulated desorption , 2011 .

[21]  M. Kivelson,et al.  Properties of the magnetic field in the Jovian magnetotail , 2002 .

[22]  R. McPherron,et al.  Average Characteristics of Triggered and Nontriggered Substorms , 2004 .

[23]  K. Liou Large, abrupt pressure decreases as a substorm onset trigger , 2007 .

[24]  M. Ashour‐Abdalla,et al.  Magnetic flux ropes at the high-latitude magnetopause , 1995 .

[25]  N. Ness,et al.  Substorms on Mercury , 1975 .

[26]  R. Lepping,et al.  Observations of plasmas associated with the magnetic signature of a plasmoid in the distant magnetotail , 1994 .

[27]  Daniel N. Baker,et al.  Neutral line model of substorms: Past results and present view , 1996 .

[28]  Rumi Nakamura,et al.  Hermean Magnetosphere-Solar Wind Interaction , 2007 .

[29]  C. Russell,et al.  Solar wind and substorm‐related changes in the lobes of the geomagnetic tail , 1973 .

[30]  Rumi Nakamura,et al.  Structure and dynamics of magnetic reconnection for substorm onsets with Geotail observations , 1998 .

[31]  C. Owen,et al.  Geotail observations of magnetic flux ropes in the plasma sheet , 2003 .

[32]  R. McPherron Satellite studies of magnetospheric substorms on August 15, 1968. I - State of the magnetosphere. , 1973 .

[33]  William E. McClintock,et al.  Mercury’s Complex Exosphere: Results from MESSENGER’s Third Flyby , 2010, Science.

[34]  James A. Slavin,et al.  The dayside magnetospheric boundary layer at Mercury , 2011 .

[35]  E. W. Hones,et al.  Structure of the magnetotail at 220 RE and its response to geomagnetic activity , 1984 .

[36]  T. Mukai,et al.  Statistical analysis of the plasmoid evolution with Geotail observations , 1998 .

[37]  D. Baker,et al.  A model of impulsive acceleration and transport of energetic particles in Mercury's magnetosphere , 1986 .

[38]  M. Dunlop,et al.  The magnetic structure of an earthward-moving flux rope observed by Cluster in the near-tail , 2007 .

[39]  T. Moretto,et al.  Coordinated observations demonstrating external substorm triggering , 1997 .

[40]  E. W. Hones,et al.  Plasmoid-associated energetic ion bursts in the deep geomagnetic tail: Properties of plasmoids and the postplasmoid plasma sheet , 1987 .

[41]  R. McPherron,et al.  SOLAR WIND DRIVERS FOR STEADY MAGNETOSPHERIC CONVECTION , 2005 .

[42]  R. McPherron,et al.  Steady magnetospheric convection: Statistical signatures in the solar wind and AE , 2002 .

[43]  Mehdi Benna,et al.  MESSENGER Observations of Extreme Loading and Unloading of Mercury’s Magnetic Tail , 2010, Science.

[44]  R. Rankin,et al.  Sodium ion exosphere of Mercury during MESSENGER flybys , 2010 .

[45]  H. Hasegawa,et al.  Transport of solar wind into Earth's magnetosphere through rolled-up Kelvin–Helmholtz vortices , 2004, Nature.

[46]  F. Leblanc,et al.  Formation of a sodium ring in Mercury's magnetosphere , 2010 .

[47]  D. Baker,et al.  MESSENGER observations of the plasma environment near Mercury , 2009 .

[48]  Thomas E. Moore,et al.  A quantitative model of the planetary Na + contribution to Mercury’s magnetosphere , 2003 .

[49]  B. Anderson,et al.  The Magnetometer Instrument on MESSENGER , 2007 .

[50]  James A. Slavin,et al.  The Structure of Mercury's Magnetic Field from MESSENGER's First Flyby , 2008, Science.

[51]  S. Solomon,et al.  MESSENGER Observations of Magnetic Reconnection in Mercury’s Magnetosphere , 2009, Science.

[52]  S. Solomon,et al.  The space environment of Mercury at the times of the second and third MESSENGER flybys , 2011 .

[53]  Wolfgang Baumjohann,et al.  The magnetosphere of Mercury and its solar wind environment , 2004 .

[54]  C. Owen,et al.  Cluster observations of flux rope structures in the near-tail , 2006 .

[55]  C. Russell,et al.  Interplanetary magnetic field control of magnetotail magnetic field geometry: IMP 8 observations , 1994 .

[56]  James A. Slavin,et al.  Dynamic substorm injections - Similar magnetospheric phenomena at earth and Mercury , 1987 .

[57]  C. Russell,et al.  Disturbances in Mercury's magnetosphere: Are the Mariner 10 “substorms” simply driven? , 1998 .

[58]  V. Angelopoulos,et al.  An investigation of the association between steady magnetospheric convection and CIR stream interfaces , 2010 .

[59]  Robert M. Winglee,et al.  Relative timing of substorm processes as derived from multifluid/multiscale simulations: Internally driven substorms , 2009 .

[60]  Clark R. Chapman,et al.  The MESSENGER mission to Mercury: Scientific objectives and implementation , 2001 .

[61]  James A. Slavin,et al.  Response of the magnetotail to changes in the open flux content of the magnetosphere , 2004 .

[62]  G. Siscoe,et al.  Observations at the planet Mercury by the plasma electron experiment, Mariner 10 , 1976 .

[63]  Robert L. McPherron,et al.  Satellite studies of magnetospheric substorms on August 15, 1968. IX - Phenomenological model for substorms. , 1973 .

[64]  J. Slavin,et al.  Magnetotail response to prolonged southward IMF Bz intervals: Loading, unloading, and continuous magnetospheric dissipation , 2005 .

[65]  A. Otto,et al.  Magnetic reconnection induced by weak Kelvin‐Helmholtz instability and the formation of the low‐latitude boundary layer , 2006 .

[66]  L. Blomberg,et al.  Observations of Kelvin‐Helmholtz waves along the dusk‐side boundary of Mercury's magnetosphere during MESSENGER's third flyby , 2010 .

[67]  C. Jackman,et al.  Statistical properties of the magnetic field in the Kronian magnetotail lobes and current sheet , 2011 .

[68]  S. A. Boardsen,et al.  Kinetic-scale magnetic turbulence and finite Larmor radius effects at Mercury , 2011, 1104.2618.

[69]  D. Baker,et al.  ISEE 3 plasmoid and TCR observations during an extended interval of substorm activity , 1992 .

[70]  M. Fujimoto,et al.  On the peak level of tearing instability in an ion-scale current sheet: The effects of ion temperature anisotropy , 2011 .

[71]  James A. Slavin,et al.  The effect of erosion on the solar wind stand-off distance at Mercury , 1979 .

[72]  V. A. Sergeev,et al.  Steady magnetospheric convection: A review of recent results , 1996 .

[73]  E. W. Hones,et al.  Measurements of magnetotail plasma flow made with Vela 4B , 1972 .

[74]  Chaosong Huang,et al.  Magnetotail total pressure and lobe magnetic field at onsets of sawtooth events and their relation to the solar wind , 2009 .

[75]  David G. Sibeck,et al.  An ISEE 3 study of average and substorm conditions in the distant magnetotail , 1985 .

[76]  David G. Sibeck,et al.  Solar wind control of the magnetopause shape, location, and motion , 1991 .

[77]  Richard D. Starr,et al.  Mercury's Magnetosphere After MESSENGER's First Flyby , 2008, Science.

[78]  S. Cowley The causes of convection in the Earth's magnetosphere: A review of developments during the IMS , 1982 .

[79]  C. Russell,et al.  The magnetosphere of Mercury , 1988 .

[80]  Daniel N. Baker,et al.  Mercury’s magnetospheric magnetic field after the first two MESSENGER flybys , 2010 .

[81]  ’. Otto Kelvin-Helmholtz Instability at the Magnetotail Boundary: MHD Simulation and Comparison with Geotail Observations , 2022 .

[82]  G. Gloeckler,et al.  MESSENGER Observations of the Composition of Mercury's Ionized Exosphere and Plasma Environment , 2008, Science.

[83]  W. Ip,et al.  MHD simulations of the solar wind interaction with Mercury , 2002 .

[84]  C. Russell,et al.  Dependence of the near-Earth magnetotail magnetic field on storm and substorm activities , 1999 .

[85]  W. Ip Dynamics of electrons and heavy ions in Mercury's magnetosphere , 1987 .

[86]  M. Dunlop,et al.  Cluster observations of traveling compression regions in the near‐tail , 2002 .

[87]  S. Solomon,et al.  The interplanetary magnetic field environment at Mercury's orbit , 2011 .

[88]  S. Solomon,et al.  Space environment of Mercury at the time of the first MESSENGER flyby: Solar wind and interplanetary magnetic field modeling of upstream conditions , 2009 .

[89]  Robert L. Tokar,et al.  Plasmoids in Saturn's magnetotail , 2008 .

[90]  E. Harnett,et al.  Erosion of the dayside magnetosphere at Mercury in association with ion outflows and flux rope generation , 2008 .

[91]  Wing-Huen Ip,et al.  A hybrid simulation of Mercury's magnetosphere for the MESSENGER encounters in year 2008 , 2010 .

[92]  R. D. Belian,et al.  Observations of magnetospheric substorms occurring with no apparent solar wind/IMF trigger , 1996 .

[93]  James A. Slavin,et al.  The Magnetic Field of Mercury , 2010 .

[94]  E. Kallio,et al.  Surface conductivity of Mercury provides current closure and may affect magnetospheric symmetry , 2004 .

[95]  Nancy U. Crooker,et al.  Dayside merging and cusp geometry , 1979 .

[96]  N. Ness,et al.  Magnetic Field Observations near Mercury: Preliminary Results from Mariner 10 , 1974, Science.

[97]  L. Blomberg,et al.  The Kelvin–Helmholtz instability at Mercury: An assessment , 2010 .

[98]  J. Slavin,et al.  Paraboloid model of Mercury's magnetosphere , 2008 .