Transcript Space Environment: An Overview

O. M. Shalabiea
Department of Physics,
Northern Borders University, KSA
Main outline
Introduction (Magnetosphere - Space Physics)
Basic structure and boundary layer
 magnetospheric plasamas
 H. Background to model the magnetosphere
Finally summary and open problems
Space missions
Magnetosphere
50,000 nT (p)
30,000 nT (Eq)
Coronal Mass Ejections:
Crossing the Earth’s Path
Magnetosphere
& Solar Wind
•mean density of about 4 cm−3,
•mean velocity of about 400 km/s,
•mean interplanetary magnetic field
(IMF) magnitude of 5 nT.
the interaction of the solar energetic particles
with electric and magnetic fields.
(the interaction of solar wind with magnetosphere)
SPACE PHYSICS
Size of the cavity (combination)
•
The solar wind dynamic
pressure: Re=10-6.6
• the magnetic pressure of
the internal field (30 Re)
Basic structure
(ESA)
Large-scale current systems in the magnetosphere.
the auroral oval, auroral electrojet currents,
- the large-scale Region 1 (more poleward)
*Region 2 (more equatorward) currents bounding the
high-latitude polar cap is shown in the background
(Figure: Teemu Makinen/Finnish Meteorological Institute).
The magnetospheric boundary layer:
1- Plasma mantle.
2- Entry layer.
4- Low-latitude boundary layer, LLBL
3- Exterior cusp.
The solar wind motional electric field in the
Earth’s frame of reference
(E = −Vsw × BIMF) imposes a large-scale
convection pattern within the magnetosphere
and ionosphere (Dungey, 1961).
Dayside reconnection allows solar wind plasma
and field entry to the dayside magnetosphere,
from where the plasma convects across
the polar cap and tail lobes to another
reconnection location in the distant tail.
Substorm on December 10, 1996. The Lyon–Fedder–Mobarry
(LFM) global MHD simulation. The color coding shows the
plasma density in the noon-midnight meridian plane.
The gray shading outlines the last closed flux surface indicating the
large-scale magnetic topology of the system.
http: // www. livingreviews. org/ lrsp-2007-1
Magnetosphere & Space Environment
• DIRECT
• It is important to study the
interaction of the solar
wind with the Earth's
• magnetosphere because
this interaction controls
space weather phenomena,
• affects on the satellite
motion and/or its attitude
control.
• INDIRECT
• On Earth’s ionosphere
Aurora:
Points of View
View From Earth
View From Space
Solar Storms & magnetoiono-spheres :
Effects On Societal Systems
Magnetospheric
plasma
the magnetospheric field in general excludes the
solar wind plasma from the magnetosphere!!!
The penetration of plasma through the magnetopause:
occurs when the IMF and the magnetospheric
fields are antiparallel and magnetic reconnection
creates an “open magnetosphere” configuration
with a field component normal to the boundary
Magnetosheath plays an important role as a mediator
between the solar wind and the terrestrial magnetosphere.
The interaction of the magnetosheath with the
magnetopause can be described in terms of waves.
The function of these waves is to reconfigure the solar
wind flow and its frozen-in magnetic field
from the solar wind state to the state specified by
the magnetopause boundary condition.
background
• Chapmann (1918), postulated that "a singly-charged beam
from the Sun cause magnetic disturbances"
• Chapmann and Ferraro (1931, 1932) a mirror field
compress the terrestrial field forming a ring of current
around the Earth in the near equatorial region, now we
refer it as "Geomagnetic storm".
• The existence of a boundary to the earth's magnetic
field.Biermann (1951),
• Through the analysis of comet tails, showed that the solar
wind is present all the times.
Background
•
•
•
•
A series of rocket flights (Van Allen belts)
Explorer 1 (1958) detect it
Then confirmation of the magnetotail
Explorer 10 (1961) gave the 1st measurements
across this boundary of radiation belts.
• Orbiting Geophysical Observatory (OGO) 1, 3, and
5 (1964) mapped the location of the bow shock
• Dungey (1961) gave the idea for the reconnection
and the importance of IMF.
Summary
• The Earth’s magnetosphere is an extremely
complicated system.
• It is shaped by the interaction between the solar
wind and the terrestrial magnetic field.
• The basic components (topology) are
the bow shock, themagnetosheath, the
magnetopause, the polar cusp, the magnetotail and
the plasma sheet.
The basic components MF (topology) are
the bow shock, themagnetosheath, the
magnetopause, the polar cusp, the
magnetotail and the plasma sheet.
Open Problems (Magnetosphere)
Sketch of the magnetosphere and the magnetotail,
Open Problems (Magnetopause)
• Not rigid Reconnection and will respond to solar
wind It will oscillate around its equilibrium state.
(more theoretical work -3D)
• Polar cusps:
How much of the plasma found in the cusp has entered
locally
By what processes, and how much simple it's transit
on its way from subsolar entry to the polar
magnetosphere.
• Boundary layer global structure and topology
Open Problems (Magnetotail)
• Ion composition
The mechanism by which cold ions of the tail lobe are heated
and fill the plasma sheet is not fully understood. How the
heating mechanisms operating at the slow shock and in the
neutral sheet to produce the plasmasheet as observed
(chemistry!!).
• Electron Acceleration
how bursts of energetic electrons with relativistic energies are
generated in the magnetotail in association with substorm
onsets.
• Coupling between the tail dynamics and the auroral:
Open Problems
(Magnetosheath)
• The interaction of the magnetosheath with the
magnetopause can be described in terms of
waves.
• These mode waves are not easy to identify
(Hubert et al., 1994).
• How and where the waves are produced still
unanswered?
• The waves in that can propagate in the
magnetosheath are one of the interesting points
for us. (MSc)
Cluster Mission (4 spacecrafts)
Rumba, Tango, Salsa and Samba.
Lost Araien 5, 96
Rumba, Tango, Salsa and Samba are
providing a detailed 3-D map of the
magnetosphere, with surprising results
Cluster is currently investigating the Earth's
magnetic environment and its interaction with the
solar wind in three dimensions. Science output
from Cluster greatly advances our knowledge of
space plasma physics, space weather and the SunEarth connection and has been key in improving
the modeling of the magnetosphere and
understanding its various physical processes .
Thanks for
ALLLLLLLLLLL
AWESOME
soon at UAE then next
door to KSA