An Analysis of Solar Energetic Particle Spectra Throughout the Inner Heliosphere
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An Analysis of Solar Energetic Particle Spectra Throughout the Inner Heliosphere J. Douglas Patterson 19th December 2002 Contents 1 Previous Studies and Results 1 1.1 Solar Structure and the Heliosphere . 1 1.2 Source of the Solar Wind and the Interplanetary Magnetic Field . 6 1.2.1 Solar Wind Outflow . 6 1.2.2 Interplanetary Magnetic Field (IMF) . 9 1.3 Global Chracteristics of the Inner Heliosphere . 10 1.3.1 The Solar Wind and Solar Magnetic Field . 10 1.3.2 Solar Energetic Particles . 10 1.3.3 Co-Rotating Interaction Regions . 12 1.3.4 Anomalous and Galactic Cosmic Rays . 12 1.4 Acceleration Processes . 13 1.4.1 DC Electric Field Acceleration . 13 1.4.2 Wave-Particle Interactions . 13 1.4.3 Shock Drift and Diffusive Acceleration . 17 2 Spacecraft Mission Descriptions 25 2.1 The Ulysses Mission . 25 2.1.1 Mission Goals and Objectives . 26 2.1.2 The Spacecraft . 26 2.1.3 Trajectory . 28 2.2 The Advanced Composition Explorer (ACE) Mission . 29 2.2.1 Mission Goals and Objectives . 29 2.2.2 The Spacecraft . 29 2.2.3 Trajectory . 31 2.3 The EPAM and the HISCALE Instruments . 31 2.3.1 The Hardware and Detector Types . 31 2.3.2 On-Board Data Processing and Data Format . 36 ii 2.3.3 Instrument-Specific Problems . 38 2.4 The IMP-8 Spacecraft and CPME Instrument . 40 2.4.1 Spacecraft and Trajectory . 42 2.4.2 Charged Particle Measurement Experiment . 42 3 Data Reduction and Analysis Procedures 46 3.1 Determination of the Background Rates for EPAM and HISCALE . 46 3.1.1 Computational Methods . 48 3.1.2 Results of Background Calculation . 56 3.2 Coordinate Systems . 57 3.3 Separation of Species in LEMS and LEFS Spectra . 61 3.3.1 Transforming the Energy Passbands . 64 3.3.2 Determining the Composition . 66 3.3.3 Determining the Proton and Alpha Particle Fluxes . 69 3.3.4 Calculating the Proton Counts in F and F’ and the Electron Flux Spectra . 71 3.3.5 Sample Results of the Separation Process . 72 4 Analysis of the Energetic Particle Spectra 78 4.1 Regional Averages of Electron and Ion Spectra for First Fast Latitude Scan . 78 4.1.1 Comparison of the Particle Spectra from the Polar Regions . 79 4.1.2 Comparison of the Particle Spectra from the Equatorial Regions . 85 4.1.3 Analysis of the Particle Spectra from the Streamer Belts . 94 4.2 Electron and Ion Spectra as a Function of the Magnetic Field Direction . 98 4.3 Comparison Between Quiet-time, Event-time Electron and Ion Spectra . 108 4.3.1 Quiet-time Proton Spectra . 108 4.3.2 Quiet-Time Electron Spectra . 109 4.3.3 Event-time Proton Spectra . 113 4.3.4 Event-time Electron Spectra . 115 5 Conclusions 119 5.1 Advantages of MFSA Data . 119 5.2 Background Rates for the HISCALE Instrument . 120 5.3 Steady-State Foreground Proton and Electron Spectra . 121 5.4 Items for Future Work . 122 5.5 Summary . 124 iii A ULYBKGR.FOR User’s Guide 125 A.1 Introduction . 126 A.2 Structure . 126 A.3 Usage . 127 A.4 Applying Updates . 128 A.5 Source Code . 128 A.5.1 ULYBKGR.FOR Source Code . 128 A.5.2 SCALE.INC Source Code . 134 A.6 References ........................................150 B MFSA_SWRF.FOR Source Code 151 iv List of Figures 1.1 Schematic of the interior layers of the Sun. [Image courtesy of ESA] . 2 1.2 Granulation resulting from convection seen in the Sun’s photosphere. [Image courtesy of NASA.] . 4 1.3 A schematic of the heliosphere. [Image courtesy of NASA] . 5 1.4 Polar plot of various particle and plasma data for the first full Ulysses orbit which oc- curred during solar minimum. The solar wind speed was measured by SWOOPS, the magnetic field polarity was measured by the FGM, and the GCRs were measured by COSPIN. Image courtesy of ESA. 11 1.5 Magnetic arcade on the solar surface imaged by the TRACE spacecraft. [Image courtesy of GSFC NASA] . 14 1.6 A schematic representation of Landau resonance. 15 1.7 Schematic of cyclotron resonance (` = 1) for a horizontally polarized electric wave. 16 1.8 Schematic of a parallel (a) and a perpendicular (b) shock. 18 1.9 A typical interplanetary oblique shock viewed in the shock boundary rest frame. 19 1.10 A simplistic cartoon of a first-order Fermi acceleration process, a head-on collision be- tween a shock front and a charged particle. 21 2.1 Schematic of the location and orientation of the major components of the Ulysses space- craft, illustration courtesy of ESA. 27 2.2 Instrument locations on the Ulysses main body, illustration courtesy of ESA. 28 2.3 Orbital trajectory for the Ulysses spacecraft; illustration courtesy of ESA. 30 2.4 An exploded view of the Advance Composition Explorer and its instruments, illustration courtesy of California Institute of Technology. 32 2.5 ACE trajectory from launch to halo orbit insertion, illustration courtesy of California Institute of Technology. 33 2.6 LEMS30/LEFS150 and LEFS60/LEMS120 Telescope Assemblies for EPAM and HIS- CALE [Lanzerotti, 1992]. 34 v 2.7 EPAM LEFS150 MFSA rates for channels 1-8 in early 1998 at the time of the LEFS150 malfunction. 41 2.8 The Charged Particles Measurement Experiment (CPME) instrument on board IMP-8, illustration courtesy of John Hopkins University Applied Physics Lab (JHU/APL). 43 2.9 The Proton-Electron Telescope (PET) on board IMP-8, illustration courtesy of JHU/APL. 44 3.1 Time series of IMP-8 P11 channel. 47 3.2 MFSA energy passbands and the correspondence to the W1, W2, and Z2 energy passbands. 50 3.3 Time series of IMP-8 P11, LW1b, and LW2b. ........................ 52 3.4 EPAM background rates for days 359 to 362 of 1997 and the modeled GCR contribution to the MFSA background spectrum. 54 3.5 Modeled LW1b and LW2b based upon the IMP-8 P11 rates for 145 MeVs<E<440 MeVs protons and the modeled EPAM background spectrum. 55 3.6 RTG contribution to the HISCALE MFSA data based upon the subtraction of the mod- eled GCR contribution from the total count rates during selected quiescent times. 56 3.7 Normalized MFSA rates for both a vertically incident and an obliquely incident RTG gamma ray spectrum [Gomez, 1996]. 58 3.8 RTG contribution to the HISCALE MFSA data as measured by a preflight laboratory measurement [Gold, 1984]. 59 3.9 Comparison between the predicted RTG induced rates [Gomez, 1996], the preflight lab- oratory measurement [Gold, 1984], and the RTG induced rates as determined by this present study. 60 3.10 Heliocentric EME and RTN coordinate systems. 61 3.11 Schematic of telescope look directions in the S/C coordinate system, the “Rosetta Stone” diagram. 62 3.12 Energy loss curves for M, F’, M’, and F for both protons and electrons given the detector parameters detailed in Table 3.3. 65 3.13 Differential flux spectra for protons and electrons on day 22 of 1999. 73 3.14 Differential flux spectra for protons and electrons on day 17 of 2000. 74 3.15 Hourly differential fluxes for protons measured by the M detector. 75 3.16 Hourly differential fluxes for electrons measured by the F’ detector. 76 3.17 Differential fluxes for day 54 of 2000. 77 4.1 Proton and electron flux through the first South Polar Pass. 81 4.2 Regionally-averaged proton spectra during the first South Polar Pass. 82 4.3 Regionally-averaged Z>1 spectra during the first South Polar Pass. 83 4.4 Regionally-averaged electron spectra during the first South Polar Pass. 84 4.5 Proton and electron flux through the first North Polar Pass. 85 vi 4.6 Regionally-averaged proton spectra during the first North Polar Pass. 86 4.7 Regionally-averaged Z>1 spectra during the first North Polar Pass. 87 4.8 Regionally-averaged electron spectra during the first North Polar Pass. 88 4.9 Proton and electron flux during the first pass through perihelion. 90 4.10 Regionally-averaged proton spectra during the first pass through.