1 / 30

O. M. Shalabiea Department of Physics, Northern Borders University, KSA

Earth’s Magnetosphere: 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

penelope
Télécharger la présentation

O. M. Shalabiea Department of Physics, Northern Borders University, KSA

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Earth’s Magnetosphere: An Overview O. M. ShalabieaDepartment of Physics, Northern Borders University, KSA

  2. 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

  3. Magnetosphere 50,000 nT (p) 30,000 nT (Eq)

  4. Coronal Mass Ejections: Crossing the Earth’s Path

  5. 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.

  6. the interaction of the solar energetic particles with electric and magnetic fields. (the interaction of solar wind with magnetosphere) SPACE PHYSICS

  7. the magnetic pressure of the internal field (30 Re) The solar wind dynamic pressure: Re=10-6.6 Size of the cavity (combination)

  8. Basic structure (ESA)

  9. 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).

  10. 1- Plasma mantle. 2- Entry layer. 3- Exterior cusp. 4- Low-latitude boundary layer, LLBL The magnetospheric boundary layer:

  11. 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.

  12. 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

  13. 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 Magnetosphere & Space Environment

  14. Aurora:Points of View View From Earth View From Space

  15. Solar Storms & magneto- iono-spheres : Effects On Societal Systems

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  21. The basic components MF (topology) are the bow shock, themagnetosheath, the magnetopause, the polar cusp, the magnetotail and the plasma sheet.

  22. Open Problems (Magnetosphere) Sketch of the magnetosphere and the magnetotail,

  23. 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

  24. 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:

  25. 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)

  26. Cluster Mission (4 spacecrafts) Rumba, Tango, Salsa and Samba. Lost Araien 5, 96

  27. Rumba, Tango, Salsa and Sambaare 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 Sun-Earth connection and has been key in improving the modeling of the magnetosphere and understanding its various physical processes.

  28. Thanks for ALLLLLLLLLLL

  29. AWESOME soon at UAE then next door to KSA

More Related