Absence of a long-lived lunar paleomagnetosphere

Determining the presence or absence of a past long-lived lunar magnetic field is crucial for understanding how the Moon’s interior and surface evolved. Here, we show that Apollo impact glass associated with a young 2 million–year–old crater records a strong Earth-like magnetization, providing evidence that impacts can impart intense signals to samples recovered from the Moon and other planetary bodies. Moreover, we show that silicate crystals bearing magnetic inclusions from Apollo samples formed at ∼3.9, 3.6, 3.3, and 3.2 billion years ago are capable of recording strong core dynamo–like fields but do not. Together, these data indicate that the Moon did not have a long-lived core dynamo. As a result, the Moon was not sheltered by a sustained paleomagnetosphere, and the lunar regolith should hold buried 3He, water, and other volatile resources acquired from solar winds and Earth’s magnetosphere over some 4 billion years.

Download Full-text

Undulations in MeV solar energetic particle fluxes in Earth's magnetosphere associated with substorm magnetic field reconfigurations

Journal of Geophysical Research Atmospheres ◽

10.1029/2012ja017618 ◽

2012 ◽

Vol 117 (A6) ◽

pp. n/a-n/a ◽

Cited By ~ 8

Author(s):

J. V. Rodriguez

Keyword(s):

Magnetic Field ◽

Energetic Particle ◽

Solar Energetic Particle ◽

Earth’S Magnetosphere ◽

Earth's Magnetosphere ◽

Particle Fluxes

Download Full-text

First in situ observation of the Moon-originating ions in the Earth's Magnetosphere by MAP-PACE on SELENE (KAGUYA)

Geophysical Research Letters ◽

10.1029/2009gl040682 ◽

2009 ◽

Vol 36 (22) ◽

Cited By ~ 44

Author(s):

Takaaki Tanaka ◽

Yoshifumi Saito ◽

Shoichiro Yokota ◽

Kazushi Asamura ◽

Masaki N. Nishino ◽

...

Keyword(s):

In Situ Observation ◽

The Moon ◽

Earth’S Magnetosphere ◽

Earth's Magnetosphere

Download Full-text

Introductory remarks

Philosophical Transactions of the Royal Society of London Series A Physical and Engineering Sciences ◽

10.1098/rsta.1994.0121 ◽

1994 ◽

Vol 349 (1690) ◽

pp. 169-170

Keyword(s):

Magnetic Field ◽

Magnetic Fields ◽

Royal Society ◽

Lunar Regolith ◽

The Moon ◽

Global Magnetic Field ◽

The Subject ◽

Planetary Missions ◽

Speculative Hypothesis ◽

First Time

This year marks not only the twenty-fifth anniversary of the first manned landing on the Moon ( Apollo 11 ) but also the thirty-fifth anniversary of the first planetary missions. The latter was the Soviet Luna 1 and 2 carrying magnetometers to test whether the Moon possessed a global magnetic field. Luna 1 passed the Moon but Luna 2 crash landed, both showed that the Moon had no magnetic field as large as 50 or 100 y (1 y = 10 -5 G = 10 -9 T). Such an experiment had been proposed by S. Chapman ( Nature 160, 395 (1947)) to test a speculative hypothesis concerning magnetic fields of cosmic bodies by P. M. S. Blackett ( Nature 159, 658 (1947)). Chapman’s suggestion was greeted by general amusement: 12 years later it was accomplished. Also two years after the launch of Sputnik 1 in 1957, Luna 3 was launched and for the first time viewed the far side of the Moon on 9 October, 1959. Laboratories from many countries were invited by NASA to take part in the analysis of rocks returned from the Apollo missions and later from the Soviet automated return of cores from the lunar regolith. British laboratories were very active in this work, and a review of the results of the new understanding of the Moon as a result of space missions formed the subject of a Royal Society Discussion Meeting in 1975 (published in Phil. Trans. R. Soc. Lond . A 285). British laboratories received samples from the automated Soviet missions that took cores from the regolith and returned them to Earth. Work on Luna 16 and 20 samples were published in Phil. Trans. R. Soc. Lond . A 284 131-177 (1977) and on Luna 24 in Phil. Trans. R. Soc. Lond . A 297 1-50 (1979).

Download Full-text

Solar wind interaction with the Earth's magnetosphere: the role of reconnection in the presence of a large scale sheared flow

Nonlinear Processes in Geophysics ◽

10.5194/npg-16-1-2009 ◽

2009 ◽

Vol 16 (1) ◽

pp. 1-10 ◽

Cited By ~ 10

Author(s):

F. Califano ◽

M. Faganello ◽

F. Pegoraro ◽

F. Valentini

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Magnetic Reconnection ◽

Large Scale ◽

Initial Conditions ◽

Magnetic Layer ◽

Magnetic Islands ◽

Solar Wind Interaction ◽

Earth’S Magnetosphere ◽

Earth's Magnetosphere

Abstract. The Earth's magnetosphere and solar wind environment is a laboratory of excellence for the study of the physics of collisionless magnetic reconnection. At low latitude magnetopause, magnetic reconnection develops as a secondary instability due to the stretching of magnetic field lines advected by large scale Kelvin-Helmholtz vortices. In particular, reconnection takes place in the sheared magnetic layer that forms between adjacent vortices during vortex pairing. The process generates magnetic islands with typical size of the order of the ion inertial length, much smaller than the MHD scale of the vortices and much larger than the electron inertial length. The process of reconnection and island formation sets up spontaneously, without any need for special boundary conditions or initial conditions, and independently of the initial in-plane magnetic field topology, whether homogeneous or sheared.

Download Full-text

Current sheets in the Earth’s magnetosphere and in laboratory experiments: The magnetic field structure and the Hall effect

Journal of Experimental and Theoretical Physics ◽

10.1134/s1063776116090119 ◽

2016 ◽

Vol 123 (4) ◽

pp. 699-715 ◽

Cited By ~ 8

Author(s):

A. G. Frank ◽

A. V. Artemyev ◽

L. M. Zelenyi

Keyword(s):

Magnetic Field ◽

Hall Effect ◽

Laboratory Experiments ◽

Field Structure ◽

Magnetic Field Structure ◽

Earth’S Magnetosphere ◽

Current Sheets ◽

Earth's Magnetosphere ◽

The Magnetic Field

Download Full-text

Calculations of the integral invariant coordinates I and L* in the magnetosphere and mapping of the regions where I is conserved

Geoscientific Model Development Discussions ◽

10.5194/gmdd-7-6413-2014 ◽

2014 ◽

Vol 7 (5) ◽

pp. 6413-6437

Author(s):

K. Konstantinidis ◽

T. Sarris

Keyword(s):

Magnetic Field ◽

Particle Motion ◽

Pitch Angle ◽

National Laboratory ◽

Space Environment ◽

Integral Invariant ◽

Earth’S Magnetosphere ◽

Starting Position ◽

Geocentric Distance ◽

Earth's Magnetosphere

Abstract. The integral invariant coordinate I and Roederer's L or L* are proxies for the second and third adiabatic invariants respectively, that characterize charged particle motion in a magnetic field. Their usefulness lies in the fact that they are expressed in more instructive ways than their counterparts: I is equivalent to the path length of the particle motion between two mirror points, whereas L*, although dimensionless, is roughly equivalent to the distance from the center of the Earth to the equatorial point of a given field line, in units of Earth radii, in the simplified case of a dipole magnetic field. However, care should be taken when calculating the above invariants, as the assumption of their adiabaticity is not valid everywhere in the Earth's magnetosphere. This is not clearly stated in state-of-the-art models that are widely used for the calculation of these invariants. In this paper, we compare the values of I and L* as calculated using LANLstar, an artificial neural network developed at the Los Alamos National Laboratory, SPENVIS, a space environment related online tool, IRBEM, a source code library dedicated to radiation belt modelling, and a 3-D particle tracing code that was developed for this purpose. We then attempt to quantify the variations between the calculations of I and L* of those models. The deviation between the results given by the models depends on particle starting position geocentric distance, pitch angle and magnetospheric conditions. Using the 3-D tracer we attempt to map the areas in the Earth's magnetosphere where I and L* can be assumed to be conserved by monitoring the constancy of I for energetic proton propagating forwards and backwards in time. These areas are found to be centered on the noon area and their size also depends on particle starting position geocentric distance, pitch angle and magnetospheric conditions.

Download Full-text

Interplanetary magnetic field rotations followed from L1 to the ground: the response of the Earth's magnetosphere as seen by multi-spacecraft and ground-based observations

Annales Geophysicae ◽

10.5194/angeo-29-1549-2011 ◽

2011 ◽

Vol 29 (9) ◽

pp. 1549-1569 ◽

Cited By ~ 6

Author(s):

M. Volwerk ◽

J. Berchem ◽

Y. V. Bogdanova ◽

O. D. Constantinescu ◽

M. W. Dunlop ◽

...

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Dynamic Pressure ◽

Earth’S Magnetosphere ◽

Solar Wind Magnetic Field ◽

Earth's Magnetosphere ◽

High Dynamic ◽

First Time ◽

Current Systems ◽

The Magnetic Field

Abstract. A study of the interaction of solar wind magnetic field rotations with the Earth's magnetosphere is performed. For this event there is, for the first time, a full coverage over the dayside magnetosphere with multiple (multi)spacecraft missions from dawn to dusk, combined with ground magnetometers, radar and an auroral camera, this gives a unique coverage of the response of the Earth's magnetosphere. After a long period of southward IMF Bz and high dynamic pressure of the solar wind, the Earth's magnetosphere is eroded and compressed and reacts quickly to the turning of the magnetic field. We use data from the solar wind monitors ACE and Wind and from magnetospheric missions Cluster, THEMIS, DoubleStar and Geotail to investigate the behaviour of the magnetic rotations as they move through the bow shock and magnetosheath. The response of the magnetosphere is investigated through ground magnetometers and auroral keograms. It is found that the solar wind magnetic field drapes over the magnetopause, while still co-moving with the plasma flow at the flanks. The magnetopause reacts quickly to IMF Bz changes, setting up field aligned currents, poleward moving aurorae and strong ionospheric convection. Timing of the structures between the solar wind, magnetosheath and the ground shows that the advection time of the structures, using the solar wind velocity, correlates well with the timing differences between the spacecraft. The reaction time of the magnetopause and the ionospheric current systems to changes in the magnetosheath Bz seem to be almost immediate, allowing for the advection of the structure measured by the spacecraft closest to the magnetopause.

Download Full-text