Planetary magnetospheres and aurorae

Duration

20h Th, 10h Pr

Number of credits

Lecturer

Denis Grodent

Language(s) of instruction

English language

Organisation and examination

Teaching in the second semester

Schedule

Schedule online

Units courses prerequisite and corequisite

Prerequisite or corequisite units are presented within each program

Learning unit contents

Planetary magnetospheres and Aurorae
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.

Learning outcomes of the learning unit

List of subjects discussed in the course
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. Space missions Our laboratory is involved in a series of space missions such as JUNO, JUICE and Cassini as well as space observatories like HST ... These examples are used to describe the different stages and ingredients of a planetary space mission.

Prerequisite knowledge and skills

Corequisite: SPAT0055 (or SPAT0048)
(It might be useful to follow courses SPAT0001, SPAT0029)

Planned learning activities and teaching methods

Problems and practical work A personal or team work will be requested. It will be presented individually during the final examination. Several activities are possible. They may rest on the Planeterrella experiment and the observation of Jupiter's radio auroral emissions.
http://lpap.ulg.ac.be/cms/c_3478754/en/lpap-planeterrella
 

Mode of delivery (face-to-face ; distance-learning)

Face-to-face, power point presentations.

Recommended or required readings

Copies of the (updated) power point lectures and reference book chapters may be downloaded from the MyULg web site.

Assessment methods and criteria

Oral examination including individual (or team) work presentation as well as general questions about the course.

Work placement(s)

Organizational remarks

It is highly recommended to attend the classes.

Contacts

Prof Denis Grodent d.grodent@uliege.be
Laboratory for Planeatary and Atmospheric Physics
Space sciences, Technologies and Astrophysics Research (STAR) Institute
Université de Liège Institut d'Astrophysique et de Géophysique Quartier AGORA (B5c) Allée du Six Août, 19C  B-4000 Liège, Belgium
phone: +32 4 366 9773 http://www.lpap.uliege.be

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