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University of New Hampshire University of New Hampshire Scholars' Repository Doctoral Dissertations Student Scholarship Summer 2019 Effects of the Solar Cycles and Longer-Term Solar Variations: Modulation of Galactic Cosmic Radiation and Filtration of Neutral Atoms from the Local Interstellar Medium Fatemeh Rahmanifard University of New Hampshire, Durham Follow this and additional works at: https://scholars.unh.edu/dissertation Recommended Citation Rahmanifard, Fatemeh, "Effects of the Solar Cycles and Longer-Term Solar Variations: Modulation of Galactic Cosmic Radiation and Filtration of Neutral Atoms from the Local Interstellar Medium" (2019). Doctoral Dissertations. 2483. https://scholars.unh.edu/dissertation/2483 This Dissertation is brought to you for free and open access by the Student Scholarship at University of New Hampshire Scholars' Repository. It has been accepted for inclusion in Doctoral Dissertations by an authorized administrator of University of New Hampshire Scholars' Repository. For more information, please contact [email protected]. Effects of the Solar Cycles and Longer-Term Solar Variations: Modulation of Galactic Cosmic Radiation and Filtration of Neutral Atoms from the Local Interstellar Medium BY Fatemeh Rahmanifard B.Sc., Amirkabir University of Technology, 2007 M.Sc., Amirkabir University of Technology, 2011 THESIS Submitted to the University of New Hampshire in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Physics September, 2019 ALL RIGHTS RESERVED c Year My Name ii This thesis has been examined and approved in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Physics by: Thesis Director, Dr. Nathan Schwadron, Presidential Chair, Norman S. and Anna Marie Waite Physics Professor Dr. Eberhard M¨obius,Physics Professor Emeritus Dr. Martin Lee, Physics Professor Emeritus Dr. Lynn Kistler, Physics Professor Dr. Karsten Pohl, Physics Professor On July 22, 2019. Original approval signatures are on file with the University of New Hampshire Graduate School. iii DEDICATION To my mom and dad, to my sisters, to my brother, and to Hamid, for being who they are. iv ACKNOWLEDGEMENTS First and foremost, I would like to thank my advisor, Nathan Schwadron, for being a source of inspiration and support, and for teaching me what it takes to be a physicist. I am thankful for Eberhard M¨obiuswho has been an endless source of knowledge and pa- tience. I appreciate all the time and effort he devoted to answering my questions. I would also like to thank Marty Lee, Lynn Kistler, and Karsten Pohl for accepting to serve on my committee and for setting good examples of dedicated scientists. Many thanks to all my friends and colleagues at UNH, on the IBEX team, on the CRaTER team, and to my amazing coauthors from whom I learned a lot. v TABLE OF CONTENTS DEDICATION iv ACKNOWLEDGEMENTS v LIST OF TABLES ix LIST OF FIGURES x LIST OF ACRONYMS xiii ABSTRACT xvi 1 Introduction 1 1.1 From The Milky Way to Our Solar System . .1 1.2 An Overview of This Research . .4 2 Variations of the Heliospheric Magnetic Field with Solar Cycles 8 2.1 Introduction . .8 2.2 HMF Variations with Solar Cycles . .9 2.2.1 Steady-State HMF . .9 2.2.2 HMF at Solar Minimum . 12 2.2.3 HMF at Solar Maximum . 13 2.2.4 Evolution of the HMF through a Solar Cycle . 15 2.3 Long-Term Variations of the HMF . 19 vi 2.4 Conclusion . 20 3 Inferring the Heliospheric Magnetic Field Back through the Maunder Min- imum (Study 1) 21 3.1 Introduction . 21 3.2 Theory and Background . 25 3.2.1 Sources and Losses of the Ambient Heliospheric Magnetic Field . 25 3.2.2 Heliospheric Magnetic Flux System . 28 3.2.3 Frequency of Coronal Mass Ejections . 30 3.2.4 Paleocosmic Radiation (PCR) Data . 31 3.2.5 Chi-Square Analysis . 32 3.3 Results . 34 3.4 Discussion . 40 3.5 Summary and Conclusion . 49 4 An Example of Radiation Risk from Solar Energetic Particles, September 2017 Event (Study 2) 52 4.1 Intorduction . 52 4.2 Cosmic Ray Telescope for the Effects of Radiation . 54 4.3 The SEP Hazard During Periods of Weak Activity . 55 4.4 Conclusion . 57 5 Characterization of the Space Radiation Environment Through a Modern Secular Minimum (Study 2) 63 5.1 Introduction . 63 5.2 CRaTER Data . 64 5.3 Galactic Cosmic Rays . 64 5.4 Modulation Potential . 66 5.5 Predictions of Solar Activity . 73 vii 5.6 Extreme Scenarios for a Modern Minimum . 75 5.7 Conservative Radiation Risks Based on Extreme Scenarios . 79 5.8 Summary and Conclusion . 85 6 Radiation Pressure from Interstellar Hydrogen Observed by IBEX Through Solar Cycle 24 (Study 3) 88 6.1 Introduction . 88 6.2 ISN H Trajectory . 93 6.3 ISN H Distribution Function . 94 6.4 Instrument Description . 97 6.5 Data Selection . 98 6.6 Shift of the ISN H peak longitude over time . 100 6.7 Discussion . 102 6.8 Summary and Conclusion . 109 7 Variations of the Radiation Pressure with Time and Radial Velocity (Study 3) 114 8 Conclusions and Outlook 120 LIST OF REFERENCES 124 A Derivation of Parker Spirals 144 B Sunspot Group Number 146 viii LIST OF TABLES 3.1 Reduced χ2 values and parameters found for cases investigated in this study using different toroidal field components and for the two cases with parameters from Smith et al. (2013) using the old and new sunspot numbers. 42 5.1 Minimum and maximum values obtained for the modulation potential and permissible missions duration (PMD) based on a Dalton-like and a Gleissberg- like cycle 25. For the case without a floor, we have applied the correlation obtained for cycle 24 to expected cycle 25 scenarios. For the case with the floor, we have applied the same correlation and raised all modulation values so that the minimum values reach the 420 MV floor in BON14 model. 84 6.1 Parameters associated with the ISN H distribution function (identical to those used by Kowalska-leszczynska et al., 2018). 97 6.2 H transmission function essential parameters for E-Step 1 and 2. 98 ix LIST OF FIGURES 1.1 A schematic view of the heliospheric interface . .4 1.2 An Overview of This Research . .7 2.1 Steady-state solar magnetic field in the ecliptic plane . 11 2.2 Ideal Parker spirals . 12 2.3 Summary of Ulysses observations . 14 2.4 The internal rotation profile of the Sun . 17 2.5 A sketch of the evolution of the HMF . 18 2.6 Reconstructions of the total open solar flux since 1610 . 20 3.1 Three processes responsible for transformation of CMEs . 27 3.2 CME rate derived from sunspot number . 32 3.3 chi-square analysis to find parameters involved in the balance of the helio- spheric magnetic flux . 35 3.4 The HMF time series since 1610, assuming a constant toroidal field . 36 3.5 Constant toroidal field versus toroidal field that scales with the mean field . 38 3.6 The HMF time series since 1610, assuming the toroidal component scales with the mean field . 39 3.7 Compairing HMF predictions from this work with previous work . 44 3.8 10Be variability . 47 3.9 HMF inversion . 49 4.1 CRaTER instrument . 59 x 4.2 CRaTER observed dose rates over cycle 24 . 60 4.3 Accumulated doses on the lunar surface during the September 2017 event . 61 4.4 Large X-class flares that began the September 2017 event with lunar dose rates and proton flux reported by CRaTER and PREDICCS during this event 62 5.1 Comparing dose rates measured by D1-D2 detector pair with and without coincidence conditions . 65 5.2 Variations of GCRs count rates with solar cycles . 67 5.3 The correlation between the modulation potential, the HMF strength, and global solar wind speed . 74 5.4 Recent decline in solar activity, compared to previous secular minima . 76 5.5 Prediction of the modulation potential for a Dalton-like and a Gleissberg-like cycle 25 . 79 5.6 HMF, solar wind speed, and modulation potential through space age and extending to a speculated cycle 25 . 83 5.7 predicted modulation potential and dose rates for a Dalton-like and a Gleissberg- like cycle 25 . 85 5.8 predicted PMD for male and female 45-year-old astronauts behind a 20 g=cm2 Al shielding for a Dalton-like and a Gleissberg-like cycle 25 . 86 6.1 Schematic view of the trajectory of the ISN atoms . 94 6.2 Distribution function of ISN H flow in IBEX-inertial frame at 1 AU overlaid on the normalized energy transmission function for E-Step 1 and E-Step 2 . 99 6.3 A Gaussian function fitted to ISN H observed count rates . 102 6.4 aFINM predictions for ISN H . 103 6.5 Variations of the ISN H flow peak longitude and the resulting radiation pa- rameter with solar activity . 111 xi 6.6 ISN H atoms trajectories for two cases of the Sun transiting to a solar mini- mum/maximum as the atoms reach 1 AU . 112 6.7 Comparing µeff with µ0, µ(vr=-25 km/s), and µ(vr=-35 km/s) from Kowalska- Leszczynska et al. (2018) . 112 6.8 µeff versus total irradiance from LASP . 113 7.1 Observed profiles of disk-averaged solar Lyα .................. 117 7.2 Radiation profile for the years 2009, 2012, and 2017 . 118 7.3 Simulated trajectory, radial velocity, net force, µ, and µ0 for an ISN H atom starting from 100 AU . 119 B.1 The old sunspot number compared to the new sunspot number .
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