DTIC ADA249868: High-Latitude Spacecraft Charging in Low-Earth Polar Orbit

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High-Latitude Spacecraft Charging In Low-Earth Polar
Orbit
6. AUTHOR(S)
Thomas B. Frooninckx, Capt
7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION
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AFIT Student Attending:Utah State University AFIT/CI/CIA-91-119
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Approved for Public Release lAW 190-I
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ERNEST A. HAYGOOD, Captain, USAF
Executive Officer
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MAY 111992
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HIGH-LATITUDE SPACECRAFT CHARGING
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IN LOW-EARTH POLAR ORBIT
by
I Thomas B. Frooninckx
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A thesis submitted in partial fulfillment
of the requirements for the degree
of
MASTER OF SCIENCE
* in
Physics
(Upper Atmospheric Option)
*IA pproved:
Jan aWilliam R. Pendleton Jr.
Ma mmittee Member
i W. John Raitt
Committee Member Dean of Graduate Studies
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UTAH STATE UNIVERSITY
Logan, Utah
* 1991
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Copyright © Thomas Brian Frooninckx 1991
All Rights Reserved
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ACKNOWLEDGEMENTS
The United States Air Force Institute of Technology sponsored my education at
Utah State University, and the Center for Atmospheric and Space Sciences Theory
Group provided research funding. I am extremely grateful for having had such an
opportunity.
I thank Dr. Jan Sojka for his shared expertise, critical review, and encouragement
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in preparing this thesis. I have benefitted professionally and personally from our
discussions (including those in the hallway, elevator, and parking lot) and am fortunate
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he served as my major professor.
The contributions of Mr. Kim Marshall, VAX Systems Manager, were invaluable.
I appreciate his assistance in developing computer codes to manage this study's
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voluminous data base.
K. Lutz and G. Deuel of the National Geophysical Data Center provided extensive
precipitating particle data sets, and F. Rich and J. James of the Geophysics Laboratory
kindly furnished ambient plasma data and technical assistance.
Finally, I wish to recognize my parents, Mom and Dad. They possess my love,
respect, and admiration.
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T. Frooninckx
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TABLE OF CONTENTS
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Page
* ACKNOWLEDGEMENTS ............................................................... ii
LIST OF TABLES ......................................................................... v
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LIST OF FIGURES ....................................................................... vi
ABSTRACT ................................................................................ viii
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Chapter
I. INTRODUCTION ................................................................... 1
II. HISTORICAL AND THEORETICAL PERSPECTIVE ........................ 3
2.1 Definition ..................................................................... 3
2.2 Previous Charging Studies ................................................. 6
2.3 Sources of Charging ........................................................ 8
2.4 Spacecraft Charging Effects .......................... 13
2.5 Charging Models and Predictions ......................................... 14
III. DEFENSE METEOROLOGICAL SATELLITE PROGRAM .................. 16
3.1 Satellite Orbits ............................................................... 16
3.2 Precipitating Electron and Ion Detector ................................... 18
3.3 Thermal Plasma Detector ................................................. 24
IV. PREVIOUS STUDY OF DMSP CHARGING .................................. 26
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4.1 Charging Results ............................................................ 26
4.2 Model Electron Spectral Characteristics ................................. 30
4.3 Charging Identification ..................................................... 33
4.4 Solar Cycle Phase .......................................................... 34
V. DMSP CHARGING -- SOLAR MAXIMUM ................................... 38
5.1 Data Base ..................................................................... 38
5.2 Charging Identification Theory ............................................ 38
5.3 Experimental Methods ...................................................... 40
5.4 Solar Maximum Charging Results ...................................... 42
VI. DMSP CHARGING -- SOLAR MINIMUM ..................................... 49
6.1 D ata Base ..................................................................... 49
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6.2 Experimental Methods ...................................................... 49
6.3 Solar Minimum Charging Results ........................................ 50
VII. DISCUSSION ..................................................................... 69
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7.1 Solar Cycle Dependence .................................................. 69
7.2 Electrons Generating a Potential ........................................... 70
7.3 The Role of Secondary Electrons ....................................... 71
7.4 Ambient Plasma Densities .................................................. 72
7.5 Location of Events .......................................................... 72
7.6 Charging at Lower Altitudes ............................................. 73
VIII. CONCLUSION ................................................................... 74
8.1 Conclusions ................................................................ 74
8.2 Recommendations for Further Study .................................... 75
i REFERENCES ........................................................................... 76
Appendix A: Summary of Charging Events ......................................... 81
Appendix B: Charging Time History for Select Events ............................. 90
Appendix C: SSJ/4 Count Rate Conversion Factors ............................... 96
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* LIST OF TABLES
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Table Page
1. F8 SSJ/4 Energy Channel Configuration ......................................... 19
2. Summary of Charging Events Reported by Gussenhoven et al. [ 1985] ....... 27
3. Charging Electron Spectra Characteristics ........................................ 32
4. Summary of Charging Event During Solar Maximum .......................... 43
5. Frequency (seconds) of ,9.7 keV Electron Fluxes Greater than
108.5 (electrons/cm2 sec ster) During Solar Maximum ......................... 48
6. Frequency (seconds) of Total Electron Fluxes Greater than 109-3
(electrons/cm2 sec ster) During Solar Maximum ................................. 48
7. Electron Spectra Characteristics During Solar Minimum Charging Events.... 59
8. Model Ambient Plasma Densities (Loglo cm"3) at 800 Kilometers and
1300 UT for Three Levels of Solar Flux and Low and Medium Levels
* of M agnetic Activity ................................................................ 64
9. Frequency (seconds) of 29.6 keV Electron Fluxes Greater than 108.5
(electrons/cm2 sec ster) During Solar Minimum ................................. 66
10. Frequency (seconds) of Total Electron Fluxes Greater than 109.3
(electrons/cm2 sec ster) During Solar Minimum ................................. 66
11. Summary of Solar Minimum Charging Events ................................... 82
12. DMSP F6 SSJ/4 Energy Channel Configuration and Factors
(Loglo) which Convert Count Rates to Various Quantities ..................... 97
13. DMSP F7 SSJ/4 Energy Channel Configuration and Factors
(Logio)w hich Convert Count Rates to Various Quantities ..................... 98
14. DMSP F8 SSJ/4 Energy Channel Configuration and Factors
(Loglo) which Convert Count Rates to Various Quantities ..................... 99
15. DMSP F9 SSJ/4 Energy Channel Configuration and Factors
(Loglo) which Convert Count Rates to Various Quantities ..................... 100
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LIST OF FIGURES
Figure Page
1. Charge sheath for symmetrically charged sphere in the presence
of a plasm a ............................................................................ 5
2. Secondary electron yield coefficients for kapton due to incident
electrons normal to surface .......................................................... 11
3. Orbital coverage of the DMSP F6, F7, F8, and F9 satellites in corrected
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geomagnetic latitude and magnetic local time over the high-latitude
northern hemisphere ................................................................. 17
4. Channel pass bands (channels 19 through 12) for the DMSP F8
SSJ/4 ion detector ................................................................... 23
5. The electron integral number flux for the SSJ/4 total energy range
(solid line) and for energies >14 keV (dotted line), and the DMSP
F6 satellite potential during a charging event on November 26, 1983 ....... 29
6. Four spectral types of precipitating kiloelectronvolt electrons during
DMSP charging events reported by Gussenhoven et al. [ 1985] ................ 31
7. Ion distribution function during -314 volt charging event on
November 26, 1983, and ion counts in each of the F7's SSJ/4
energy channels ...................................................................... 35
8. Solar flux levels (10.7 cm) during January, November, and
December of 1983 with arrows denoting days of DMSP charging ............. 36
9. Solar 10.7 cm flux levels (top) and 3 hovr Kp sums (bottom) during
winter periods of solar maximum (1989-90) and solar minimun
(19 86-87) .............................................................................. 39
10. Distribution functions for electrons (left) and ions (right) during -45
volt charging event on November 13, 1989 ...................................... 45
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11. Electron distribution function during -45 volt charging event in relation
to a greater electron distribution which did not generate charging .............. 46
12. DMSP charging levels and durations of events occurring during
I solar m inim um ....................................................................... 52
13. Positions of F6 and F7 satellites in corrected geomagnetic latitude and
magnetic local time during solar minimum charging events ..................... 53
14. Positions of F6 satellite in corrected geomagnetic latitude and magnetic
local time during solar minimum charging events ................................ 54
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15. Positions of F7 satellite in corrected geomagnetic latitude and magnetic
local time during solar minimum charging events ................................ 55
16. Satellite potential plotted as a function of the total electron integral
num ber flux .......................................................................... 57
17. Satellite potential plotted as a function of the electron integral number
flux for energies 29.6 keV .......................................................... 58
18. Electron integral number fluxes for energies above 1 keV during
two extreme DMSP charging events ............................. 61
3 19. TDIM-generated plasma pattern and densities Ooglo) at 800 kilometers
during a winter period of low solar flux and low magnetic activity ............ 63
20. Satellite potential plotted as a function of the 3 hour Kp index ................. 68
21. The electron integral number flux for the SSJ/4 total energy range
(solid line) and for energies 29.6 keV (dotted line), and the DMSP
F7 satellite potential (dashed line) during a charging event on
January 11, 1987 ..................................................................... 91
22. The electron integral number flux for the SSJ/4 total energy range
(solid line) and for energies >9.6 keV (dotted line), and the DMSP
F6 satellite potential (dashed line) during a charging event on
Decem ber 31, 1986 ................................................................. 92
23. The electron integral number flux for the SSJ/4 total energy range
(solid line) and for energies >9.6 keV (dotted line), and the DMSP
F7 satellite potential (dashed line) during severe charging events on
January 27, 1987, (top) and December 16, 1986, (bottom) .................... 93
24. The electron integral number flux for the SSJ/4 total energy range
(solid line), for energies .3 keV (long dashes), and for energies 29.6 keV
(dotted line), and the DMSP F7 satellite potential (short dashes) during a
charging event on January 31, 1987 ............................................... 94
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ABSTRACT
High-Latitude Spacecraft Charging
In Low-Earth Polar Orbit
by
Thomas B. Frooninckx, Master of Science
Utah State University, 1991
Major Professor: Dr. Jan J. Sojka
Department: Physics
Spacecraft charging within the upper ionosphere is commonly thought to be
insignificant and thus has received little attention. Recent experimental evidence has
shown that electric potential differences as severe as -680 volts can develop between
Defense Meteorological Satellite Program (DMSP) polar-orbiting (840 kilometers)
spacecraft and their high-latitude environment. To explore space vehicle charging in
this region more fully, an analysis was performed using DMSP F6, F7, F9. and F9
satellite precipitating particle and ambient plasma measurements taken during the
winters of 1986-87 (solar minimum) and 1989-90 (solar maximum).
An extreme solar cycle dependence was discovered as charging occurred more
frequently and with greater severity during the period of solar minimum. One hundred
seventy charging events ranging from -46 to -1,430 volts were identified, and satellite
measurements and Time Dependent Ionospheric Model (TDIM) output were used to
characterize the environments which generated and inhibited these potentials. All
current sources were considered to determine the cause of the solar cycle dependence. ,
The examination of precipitating electron populations associated with various
DMSP charging levels suggested that electrons greater than 2 keV can contribute to a
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