Code: | AST3005 | Acronym: | AST3005 |
Keywords | |
---|---|
Classification | Keyword |
OFICIAL | Astronomy |
Active? | Yes |
Responsible unit: | Department of Physics and Astronomy |
Course/CS Responsible: | Bachelor in Chemistry |
Acronym | No. of Students | Study Plan | Curricular Years | Credits UCN | Credits ECTS | Contact hours | Total Time |
---|---|---|---|---|---|---|---|
L:B | 0 | Official Study Plan | 3 | - | 6 | 56 | 162 |
L:F | 38 | Official Study Plan | 2 | - | 6 | 56 | 162 |
3 | |||||||
L:G | 0 | study plan from 2017/18 | 3 | - | 6 | 56 | 162 |
L:M | 0 | Official Study Plan | 3 | - | 6 | 56 | 162 |
L:Q | 0 | study plan from 2016/17 | 3 | - | 6 | 56 | 162 |
In the first part of the course, we will introduce the fundamental tools and concepts in fluid mechanics and some applications of this theory to physics and astrophysics. In the second part, this approach will be extended to the study of plasmas and particular emphasis on the orbital theory of plasmas and on magnetohydrodynamics (MHD) will be devoted. At the end of the course, some examples of applications of MHD to the sun and to other astronomical objects will be treated.
Being able to understand a number of phenomena associated with the behaviour of neutral fluids either in the ideal limit or considering the effects of viscosity. Being able to understand the behaviour of plasmas and some of the phenomena associated with them either in the limit without collisions or in the limit dominated by collisions.
PART 1: FLUIDS
1. Introduction Fluids and plasmas in Physics and Astrophysics
2. Ideal fluid Properties Derivation of macroscopic equations of hydrodynamics. The equation of continuity. The equation of motion - Euler's equation. The energy equation. The condition for absence of convection. The flow of energy and the flow of momentum. Barotropic and incompressible fluids. The conservation of motion. The Kelvin's vorticity theorem. The Bernoulli principle for stationary flows. Hydrostatics. Forces on submerged solid surfaces. Modelling the solar corona. Potential flow. Flow around a cylinder Stream function.
3. Viscous fluids Properties. Tangential stresses in a Newtonian fluid. The Navier-Stokes equations. Energy dissipation in incompressible fluids. Flow between two parallel planes subjects, in a circular tube and between two rotating cylinders. Factors of scale and the Reynolds number. Viscous flows around solid bodies. Boundary layers. Accretion disks in astrophysics: dynamics of accretion disks; stationary solutions.
4. Linear theory of waves and instabilities The philosophy of the analysis of disturbances. Convective instability and internal gravity waves: the Schwarzschild criterion. Surface gravity waves. Disturbances in the separation between two fluids: the Rayleigh-Taylor instability; Kelvin-Helmholtz instability. Jeans instability and the process of star formation. Oscillations in stars. Helioseismology.
PART 2: PLASMAS
5. Plasma physics: plasma orbital theory, dynamics of multiple charged particles and processes without collisions in plasmas. Approaches used in the theory of plasmas Orbits of motion of particles in a plasma. Effect of a perpendicular force, gradient and curvature. Larmor radius and frequency. Magnetic mirrors. Particle acceleration in astrophysics. Van Allen Belt. Cosmic rays. Basic properties of plasmas. Different types of plasma. Electrical neutrality in a plasma. Shielding and the Debye length. The plasma parameter. Oscillations in plasmas. The plasma frequency. Electromagnetic waves in hot and cold plasmas.
6. Magnetohydrodynamics (MHD): Fundamental equations. The plasma equations. The equation of induction and its consequences. Magnetohydrostatics.
7. Applications of MHD: The buoyancy of magnetic flux tubes. The Parker instabilityof the magnetic field. The magnetic field as a carrier of angular momentum, magnetic braking and magnetized winds. Magnetic reconnection and application solar flares.
Expository methods in theoretical lectures (T). In theoretical-practical classes (TP) resolution of exercises by the students.
designation | Weight (%) |
---|---|
Exame | 100,00 |
Total: | 100,00 |
designation | Time (hours) |
---|---|
Estudo autónomo | 106,00 |
Frequência das aulas | 56,00 |
Total: | 162,00 |
The student has frequency to the course if he/she misses no more than 1/4 of the planned theoretical-practical classes (TP's).
Final Mark = Exam Mark
It is possible to improve grades through the 2nd season exam.
The jury fo the curricular unit includes the following lecturers:
João Lima
Mário Monteiro
Jorge Gameiro