dc.contributor.author |
Hiremath, K. M |
|
dc.date.accessioned |
2011-05-16T16:12:35Z |
|
dc.date.available |
2011-05-16T16:12:35Z |
|
dc.date.issued |
2012-04 |
|
dc.identifier.citation |
Planetary and Space Science, Vol. 63–64, pp. 8–14 |
en |
dc.identifier.uri |
http://hdl.handle.net/2248/5467 |
|
dc.description.abstract |
Recently planet Mercury-an unexplored territory in our solar system-has been of much interest to
the scientific community due to recent flybys of the spacecraft MESSENGER that discovered its
intrinsic stationary and large-scale dipole like magnetic field structure with a intensity of ∼ 300
nTesla confirming Mariner 10 observations. In the present study, with the observed constraint
of Mercury’s atmospheric magnetic field structure, internal magnetic field structure is modeled
as a solution of magnetic diffusion equation. In this study, Mercury’s internal structure mainly
consists of a stable stratified fluid core and the convective mantle. For simplicity, magnetic
diffusivity in both parts of the structure is considered to be uniform and constant with a value
represented by a suitable averages. It is further assumed that vigorous convection in the mantle
disposes of the electric currents leading to a very high diffusivity in that region. Thus, in order
to satisfy observed atmospheric magnetic field structure, Mercury’s most likely magnetic field
structure consists of a solution ofMHD diffusion equation in the core and a combined multipolar
(dipole and quadrupole like magnetic field structures embedded in the uniform field) solution of
a current free like magnetic field structure in the mantle and in the atmosphere. With imposition
of appropriate boundary conditions at the core-mantle boundary for the first two diffusion
eigen modes, in order to satisfy the observed field structure, present study puts the constraint on
Mercury’s core radius to be ∼ 2000 km.
From the estimated magnetic diffusivity and the core radius, it is also possible to estimate
the two diffusion eigen modes with their diffusion time scales of the ∼ 8.6 and 3.7 billion yrs
respectively suggesting that the planet inherits its present day magnetic field structure from the
solar nebula. It is proposed that permanency of such a large-scale magnetic field structure of
the planet is attained during Mercury’s early evolutionary history of heavy bombardments by the
asteroids and comets supporting the giant impact hypothesis for the formation of Mercury |
en |
dc.language.iso |
en |
en |
dc.publisher |
Elsevier B.V. |
en |
dc.relation.uri |
http://dx.doi.org/10.1016/j.pss.2011.04.011 |
|
dc.rights |
© Elsevier B.V. |
en |
dc.subject |
Mercury |
en |
dc.subject |
Magnetic Field structure |
en |
dc.subject |
Giant impacts |
en |
dc.subject |
Origin and Formation of Mercury |
en |
dc.subject |
Planetary Craters |
en |
dc.subject |
MESSENGER and BepiColombo missions |
en |
dc.title |
Magnetic Field Structure of Mercury |
en |
dc.type |
Article |
en |