MULTI-SPACECRAFT ANALYSIS OF ENERGETIC HEAVY ION AND INTERPLANETARY SHOCK PROPERTIES IN ENERGETIC STORM PARTICLE EVENTS NEAR 1 au

We examine the longitude distribution of and relationship between interplanetary (IP) shock properties and ∼0.1–20 MeV nucleon−1 O and Fe ions during seven multi-spacecraft energetic storm particle (ESP) events at 1 au. These ESP events were observed at two spacecraft and were primarily associated with low Mach number, quasi-perpendicular shocks. Key observations include the following: (i) the Alfvén Mach number increased from east to west of the coronal mass ejection source longitude, while the shock speed, compression ratios, and obliquity showed no clear dependence; (ii) the O and Fe time intensity profiles and peak intensities varied significantly between longitudinally separated spacecraft observing the same event, the peak intensities being larger near the nose and smaller along the flank of the IP shock; (iii) the O and Fe peak intensities had weak to no correlations with the shock parameters; (iv) the Fe/O time profiles showed intra-event variations upstream of the shock that disappeared downstream of the shock, where values plateaued to those comparable to the mean Fe/O of solar cycle 23; (v) the O and Fe spectral index ranged from ∼1.0 to 3.4, the Fe spectra being softer in most events; and (vi) the observed spectral index was softer than the value predicted from the shock compression ratio in most events. We conclude that while the variations in IP shock properties may account for some variations in O and Fe properties within these multi-spacecraft events, detailed examination of the upstream seed population and IP turbulence, along with modeling, are required to fully characterize these observations.

[1]  M. Desai,et al.  Large gradual solar energetic particle events , 2016, Living reviews in solar physics.

[2]  R. Mewaldt,et al.  THE LONGITUDINAL DEPENDENCE OF HEAVY-ION COMPOSITION IN THE 2013 APRIL 11 SOLAR ENERGETIC PARTICLE EVENT , 2014 .

[3]  E. Christian,et al.  > 25 MeV Proton Events Observed by the High Energy Telescopes on the STEREO A and B Spacecraft and/or at Earth During the First ∼ Seven Years of the STEREO Mission , 2014 .

[4]  C. Cohen.  Observations of Energetic Storm Particles: An Overview , 2013 .

[5]  B. Heber,et al.  LONGITUDINAL AND RADIAL DEPENDENCE OF SOLAR ENERGETIC PARTICLE PEAK INTENSITIES: STEREO, ACE, SOHO, GOES, AND MESSENGER OBSERVATIONS , 2013 .

[6]  G. Zank,et al.  INTERPLANETARY PROPAGATION OF SOLAR ENERGETIC PARTICLE HEAVY IONS OBSERVED AT 1 AU AND THE ROLE OF ENERGY SCALING , 2012 .

[7]  D. Reames.  PARTICLE ENERGY SPECTRA AT TRAVELING INTERPLANETARY SHOCK WAVES , 2012 .

[8]  G. Zank,et al.  Particle acceleration and transport at an oblique CME-driven shock , 2012 .

[9]  N. Gopalswamy,et al.  Energetic storm particle events in coronal mass ejection–driven shocks , 2011 .

[10]  A. Szabo,et al.  Multispacecraft observations of interplanetary shock shapes on the scales of the Earth's magnetosphere , 2010 .

[11]  G. Zank,et al.  SHOCK GEOMETRY AND SPECTRAL BREAKS IN LARGE SEP EVENTS , 2009 .

[12]  J. Dwyer,et al.  COMPOSITION AND SPECTRAL PROPERTIES OF THE 1 AU QUIET-TIME SUPRATHERMAL ION POPULATION DURING SOLAR CYCLE 23 , 2008 .

[13]  Usa,et al.  QUANTITATIVE MEASUREMENTS OF CORONAL MASS EJECTION-DRIVEN SHOCKS FROM LASCO OBSERVATIONS , 2008, 0811.3743.

[14]  D. Curtis,et al.  The STEREO/IMPACT Magnetic Field Experiment , 2008 .

[15]  M. Desai,et al.  The Suprathermal Ion Telescope (SIT) For the IMPACT/SEP Investigation , 2008 .

[16]  E. Christian,et al.  The STEREO Mission: An Introduction , 2008 .

[17]  R. Ogliore,et al.  The Low-Energy Telescope (LET) and SEP Central Electronics for the STEREO Mission , 2008 .

[18]  J. Jost,et al.  The Plasma and Suprathermal Ion Composition (PLASTIC) Investigation on the STEREO Observatories , 2008 .

[19]  J. Giacalone,et al.  The Energy Spectrum of Energetic Particles Downstream of Turbulent Collisionless Shocks , 2008 .

[20]  A. Tylka,et al.  A Model for Spectral and Compositional Variability at High Energies in Large, Gradual Solar Particle Events , 2006 .

[21]  N. Gopalswamy,et al.  Solar eruptions and energetic particles , 2006 .

[22]  Gang Li,et al.  Particle acceleration at perpendicular shock waves: Model and observations , 2005 .

[23]  H. Hayakawa,et al.  Determination of shock parameters for the very fast interplanetary shock on 29 October 2003 , 2005 .

[24]  J. Giacalone,et al.  Multi-Spacecraft Observations of Interplanetary Shocks: Non-Planarity and Energetic Particles , 2005 .

[25]  W. Rice,et al.  Acceleration and transport of heavy ions at coronal mass ejection‐driven shocks , 2005 .

[26]  W. F. Dietrich,et al.  Shock Geometry, Seed Populations, and the Origin of Variable Elemental Composition at High Energies in Large Gradual Solar Particle Events , 2005 .

[27]  S. M. Krimigis,et al.  Spectral Properties of Heavy Ions Associated with the Passage of Interplanetary Shocks at 1 AU , 2004 .

[28]  W. Rice,et al.  Particle acceleration and coronal mass ejection driven shocks: Shocks of arbitrary strength , 2003 .

[29]  Charles W. Smith,et al.  ACE Observations of Energetic Particles Associated with Transient Interplanetary Shocks , 2003 .

[30]  S. M. Krimigis,et al.  Evidence for a Suprathermal Seed Population of Heavy Ions Accelerated by Interplanetary Shocks near 1 AU , 2003 .

[31]  S. Kahler.  The correlation between solar energetic particle peak intensities and speeds of coronal mass ejections: Effects of ambient particle intensities and energy spectra , 2001 .

[32]  D. Odstrcil,et al.  Three-dimensional propagation of CMEs in a structured solar wind flow: 1. CME launched within the streamer belt , 1999 .

[33]  G. Gloeckler,et al.  Investigation of the composition of solar and interstellar matter using solar wind and pickup ion measurements with SWICS and SWIMS on the ACE spacecraft , 1998 .

[34]  S. M. Krimigis,et al.  The Ultra-Low-Energy Isotope Spectrometer (ULEIS) for the ACE spacecraft , 1998 .

[35]  Norman F. Ness,et al.  The ACE Magnetic Fields Experiment , 1998 .

[36]  W. R. Cook,et al.  The Solar Isotope Spectrometer for the Advanced Composition Explorer , 1998 .

[37]  S. Kahler,et al.  Spatial and Temporal Invariance in the Spectra of Energetic Particles in Gradual Solar Events , 1997 .

[38]  M. Kallenrode.  A statistical survey of 5‐MeV proton events at transient interplanetary shocks , 1996 .

[39]  P. Lamy,et al.  The Large Angle Spectroscopic Coronagraph (LASCO): Visible light coronal imaging and spectroscopy , 1992 .

[40]  T. T. von Rosenvinge,et al.  The role of interplanetary shocks in the longitude distribution of solar energetic particles , 1988 .

[41]  R. A. Mewaldt,et al.  The Advanced Composition Explorer , 1988 .

[42]  J. Jokipii.  Rate of energy gain and maximum energy in diffusive shock acceleration , 1987 .

[43]  J. Scudder,et al.  Fast and optimal solution to the 'Rankine-Hugoniot problem'. [for geometrical shock wave properties, conservation constants and self-consistent asymptotic magnetofluid variables of interplanetary medium] , 1986 .

[44]  B. Tsurutani,et al.  Acceleration of >47 keV Ions and >2 keV electrons by interplanetary shocks at 1 AU , 1985 .

[45]  H. Cane.  The evolution of interplanetary shocks , 1985 .

[46]  T. Sanderson,et al.  The energy spectrum of 35‐ to 1600‐keV protons associated with interplanetary shocks , 1984 .

[47]  Martin A. Lee.  Coupled hydromagnetic wave excitation and ion acceleration at interplanetary traveling shocks , 1983 .

[48]  L. Drury.  An introduction to the theory of diffusive shock acceleration of energetic particles in tenuous plasmas , 1983 .

[49]  R. Decker.  The modulation of low‐energy proton distributions by propagating interplanetary shock waves: A numerical simulation , 1981 .

[50]  B. Abraham-Shrauner,et al.  Interplanetary shocks seen by Ames plasma probe on Pioneer 6 and 7 , 1976 .

[51]  R. B. Mckibben.  Azimuthal propagation of low‐energy solar‐flare protons as observed from spacecraft very widely separated in solar azimuth , 1972 .

[52]  B. Abraham-Shrauner.  DETERMINATION OF MAGNETOHYDRODYNAMIC SHOCK NORMALS. , 1972 .

[53]  T. L. Cline,et al.  Explorer 12 observations of solar cosmic rays and energetic storm particles after the solar flare of September 28, 1961 , 1962 .