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| SPAT0028-2 | Planetary magnetospheres and aurorae
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| Duration : | 20h Th, 10h Pr |
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| Credits/ECTS : |
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| Holder(s) : | Denis Grodent |
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| Language : | French language |
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| Course contents : | Polar aurorae do not only exist on Earth. They also appear on other planets and other objects in our Solar System and even in other planetary systems. These phantom-like displays are the most impressive evidence of permanent interaction between the planets and their spatial environment. In most cases, this interaction results from the combination of the Sun-Magnetosphere-Ionosphere. Other combinations exist and are just as effective at producing aurorae. We will explore the Solar System looking for such combinations. |
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| Course objective : | Preliminary plan
1. Magnetospheres
Two components are necessary to create a magnetosphere: a magnetic field and a plasma flow.
1.1 Magnetic field
Three types of planetary magnetic fields will be considered: intrinsic, inferred and residual. We will explain the origins of these fields (notably the dynamo effect) for different objects in the Solar System.
1.2 Plasma flow
1.2.1. The most obvious is the solar wind. We describe the origin of this solar plasma and its characteristics (interplanetary magnetic field, the frozen field principle, solar activity in terms of cycles, CME, CIR, ...)
1.2.2. We will also consider local plasma flows, such as the Io plasma torus around Jupiter and we will describe the origins of magnetospheric plasma.
1.3. Movements of charged particles in a planetary electromagnetic field.
We will reintroduce the concept of Maxwell equations and magnetohydrodynamics which will allow us to explain the movement of particles which are trapped in the planetary magnetic field. We will also introduce the important concept of magnetic reconnection.
1.4.
Properties of magnetospheres
Magnetospheres all have more or less the same structure. We will therefore define concepts such as magnetopause, magnetosheath, plasmasphere, magnetodisc, as well as the different electric currents which circulate in these areas.
1.5. Detailed description and comparison between the magnetospheres of Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, comets, pulsars, including their commonalities and their differences.
2. Combination of Sun-Magnetosphere-Ionosphere(SMI)
2.1. Planetary atmospheres and ionospheres
Primarily Earth, Jupiter and Saturn.
2.2. S-M combination
Dungey Cycle, magnetrospheric convection, reconnections.
2.3. M-I combination
2.3.1. Aligned currents
2.3.2. Vasyliunas Cycle, co-rotation, Hill processes
2.3.3. Interaction between satellites, Io, Ganymede, Europe, Tital, Encelade, ...
2.4 S-M-I combination
2.4.1. Magnetospheric cycles, internal and external checks on magnetosphere dynamics.
2.4.2. Storms and magnetic sub-storms, creation of plasma bubbles
3. Polar aurorae
3.1. Particle-atmosphere interactions
3.1.1. Approximation using two beams, CSDA method, ...
3.1.2. Auroral photochemistry
3.1.3. Auroral heating
3.2. Observing aurorae
3.2.1. Elements of spectroscopy
3.2.2. Auroral emissions in radio, IR, visible, UV and RX fields.
3.2.3. Relationship between colour and atmospheric survey
3.2.4. Observations from the Earth: VLT, IRTF, Nançay radiotelescope, ...
3.2.5. Observations from space: HST, IMAGE, XMM, CXO, ...
3.2.6. Observations in situ: Voyager, Ulysses, Gallileo, Cassini, Vex, Mex, JUNO
4. Future prospects and new space missions
Our laboratory is involved in a series of space projects such as JUNO and EJSM ... We use them to illustrate prospective studies in this field. |
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| Prerequisites : | Co-ordination will be required to ensure that the contents of this course are aligned with the course on "L'environnement magnétique terrestre" and the compulsory courses "Atmosphères terrestre et planétaire" and "Physique des plasmas". This course relies principally on the knowledge acquired in the field within LPAP. |
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| Workshops : | 1. Problems and practical work
A personal or team work will be requested. It will be presented individually during the final examination. |
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| Written notes : | Copies of the lectures and reference book chapters will be distributed. |
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| Assessment : | Oral examination including individual (or team) work presentation as well as general questions about the course. |
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| Contacts : | Denis GRODENT -PhD- Research Associate F.R.S. - FNRS
LPAP - Université de Liège - B5c
Institut d'Astrophysique et de Géophysique
Allée du 6 Août, 17, B-4000 LIEGE, Belgium
phone: +32 4 366 9773 fax: +32 4 366 9711
d.grodent@ulg.ac.be
http://www.ago.ulg.ac.be/Sci/plane_e.php (http://www.ago.ulg.ac.be/Sci/plane_e.php" target="_blank) |
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