The Earth's magnetic field can be decomposed into spherical harmonics, and the exact coefficients of the decomposition can be determined through a few measurements of its value at different locations. Using measurements from a magnetometer on board the International Space Station, we computed the multipolar moments of an expansion in spherical harmonics to order 3, calculated the location of the magnetic dip poles, and produced an intensity map of the magnetic field across the globe. The accuracy of the results was evaluated by comparison with data from the International Geomagnetic Reference Field.
REFERENCES
1.
2.
D.
Bartlett
, Essentials of Positioning and Location Technology
(
Cambridge U. P
.,
Cambridge
, 2013
).3.
D.
Stump
and
G.
Pollack
, “
A current sheet model for the Earth's magnetic field
,” Am. J. Phys.
66
, 802
–810
(1998
).4.
H.
Meyers
and
W.
Davis
, “
A profile of the geomagnetic model user and abuser
,” J. Geomagn. Geoelectr.
42
, 1079
–1085
(1990
).5.
R.
Merrill
,
M.
McElhinny
, and
P.
McFadde
, The Magnetic Field of the Earth
(
Academic
,
New York
, 1996
).6.
P.
Alken
et al, “
International geomagnetic reference field: The thirteenth generation
,” Earth Planets Space
73
, 49
(2021
).7.
The ESA Swarm mission is currently the primary satellite data source <https://earth.esa.int/eogateway/missions/swarm>.
8.
A.
Chulliat
,
W.
Brown
et al, The US/UK World Magnetic Model for 2020–2025: Technical Report
(
National Centers for Environmental Information, NOAA
,
Silver Spring, Maryland
, 2020
).9.
Intermagnet is a programme establishing a global network of cooperating digital magnetic observatories that facilitates data exchanges, <http://www.intermagnet.org/>.
10.
C.
Beggan
and
S.
Marple
, “
Building a Raspberry Pi school magnetometer network in the UK
,” Geosci. Commun.
1
, 25
–34
(2018
).11.
B.
Hofmann-Wellenhof
,
H.
Lichtenegger
, and
J.
Collins
, GPS-Theory and Practice
(
Springer
,
New York
,
1994
).12.
Information on the Raspberry Pi computer and on the Sense Hat can be found at the internet site of the Raspberry Pi Foundation, <https://www.raspberrypi.org/>.
13.
T.
Magalhães
et al, “
Observation of atmospheric gravity waves using a Raspberry Pi camera module on board the International Space Station
,” Acta Astronaut.
182
, 416
–423
(2021
).14.
S.
Malin
and
D.
Winch
, “
Annual variation of the geomagnetic field
,” Geophys. J. Int.
124
, 170
–174
(1996
).15.
V.
Courtillot
and
J. Le
Mouël
, “
Time variations of the Earth's magnetic field: From daily to secular
,” Ann. Rev. Earth Planet. Sci.
16
, 389
–476
(1988
).16.
T.
Sabaka
,
N.
Olsen
, and
R.
Langel
, “
A comprehensive model of the quiet-time, near-Earth magnetic field: Phase 3
,” Geophys. J. Int.
151
, 32
–68
(2002
).17.
Wolfram Mathematica is a software system, widely used by physicists and mathematicians, developed by Wolfram Research, <https://www.wolfram.com/mathematica/>.
18.
The data used in this work and the programs used to process them can be found at the GitHub repository, <https://github.com/magnetometer/iss/releases/tag/issmag>.
19.
Astro Pi Flight Data Analysis, by the Raspberry Pi Foundation, <https://github.com/raspberrypilearning/astro-pi-flight-data-analysis/raw/master/data/Columbus_Ed_astro_pi_datalog.csv.zip>.
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2022
Author(s)
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