Programme

View the detailed timetable (click to enlarge):

Lectures

Lab experiments (Rob Coker, LANL)

Sumary:

• scaling
  • philosophopy behind the concept
  • scaling the equations (and limitations thereof) for hydro, MHD & radiation
  • the resulting relevant dimensionless parameters

• facilities and diagnostics
  • present
  • future

• a sketch of how to apply scaling to jets
  • o protostellar jets (hydro)
  • AGN (MHD)

Suggested reading (ordered):

• Experimental astrophysics with high power lasers and Z pinches, by Bruce A. Remington
• Similarity Criteria for the Laboratory Simulation of Supernova Hydrodynamics, by D. D. Ryutov et al
• Criteria for Scaled Laboratory Simulations of Astrophysical MHD Phenomena, by D. D. Ryutov et al
• Astrophysical Radiation Dynamics: The Prospects for Scaling, by John I. Castor
• Fluid Mechanics, Landau & Lifshitz

Output from MHD models (Nektarios Vlahakis, Athens)

• Introduction -- definitions -- MHD equations -- physics of integrals of steady-axisymmetric flows (relativistic and nonrelativistic)
• Momentum equation: acceleration and collimation mechanisms -- their relation to the streamline-shape and the current-distribution -- asymptotic analysis: expected flow-characteristics (velocity, flow-shape, magnetic field, density) -- relation with boundary conditions
• Brief discussion on the disk-outflow connection, and analytical/numerical disk models
• Semianalytical outflow models: results -- connection with previous analysis
• Outflow simulations: results -- connection with previous analysis
• Inflow-outflow simulations
• Open problems

Suggested reading (ordered):

• Introduction to MagnetoHydroDynamics, by Guy Pelletier
• Theory of MHD jets and outflows, by Kanaris Tsinganos
• MHD disc winds, by Jonathan Ferreira
• Stellar Wind Models, by Christophe Sauty

MHD heating (Alan Hood, University of St Andrews)

Summary:

• An introduction to the Sun (for non solar physicists): description of solar phenomena, observations of photosphere, sunspots, convection, small scale magnetic fields, observations of the solar corona.
• Observational signatures of coronal heating: the energy budget and the contributions from various mechanisms (the theoretical ideas would be discussed later), the magnetic carpet.
• Theoretical ideas -- waves: MHD waves propagating in non-uniform plasmas, terminology (body, surface, kink, sausage and dispersion diagrams), observations of waves in the corona. Phase mixing, resonant absorption and observational differences.
• Theoretical ideas -- magnetic reconnection: basic ideas in reconnection theory, observations of reconnection, simulations of flux emergence (and heating), coronal tectonics (nanoflares).
• Theoretical ideas -- the plasma response: the plasma response to an input of heating.
• Recent observations from Hinode and Stereo: recent observations of sunspots, flares, prominences, small reconnection jets, CMEs, 3D movies of the Sun.

Suggested reading (ordered):

• "Heating the upper atmosphere" in Solar MHD, Eric Priest.

Flows in molecular media (David Flower, Durham)

Summary:

• Summary of flow equations in 1-D and in steady state, including a magnetic field: Discussion of the 'source' terms, which include the physical and chemical processes contributing to changes of number density, the momentum and energy fluxes, viz. chemical reactions, heating and cooling processes.
• J-type shock waves
  • Jump (Rankine-Hugoniot) conditions
  • Cooling processes behind the 'discontinuity'
  • H_2 reformation behind the discontinuity
• C-type shock waves
  
  • Importance of the magnetic field
  • Significance of the chemistry
• Evolution of J- into C-type shocks: time-dependent MHD models
• Shock waves in diffuse interstellar gas: effects arising from the ultraviolet radiation field
• Diagnostics
  • H_2 'excitation diagram'
  • Comparison of the predictions of J- and C-type shocks
  • Examples of specific outflow sources
  • Forbidden lines, e.g. [C I], [N I], [S II] and [Fe II] : mechanism of their excitation
    

Suggested reading:

• Chapter “Interstellar shocks and chemistry” of “Molecular collisions in the interstellar medium” by David Flower
• Bibliography

The ionisation and excitation state of stellar outflows (Alex Raga, UNAM)

Summary:

• Motivation: the gasdynamic description of an astrophysical flow
• The ionisation state of the gas
  
  • ionisation equilibrium, non-equilibrium, statistical equilibrium, coronal equilibrium
  • collisional ionisation, radiative+dielectronic recombination, charge exchange and photoionisation coefficients
  • integrating the non-equilibrium ionisation rate equations: analytic examples and numerical methods
• The cooling function
  
  • collisional ionisation, radiative recombination
  • recombination lines
  • collisionally excited lines (by electrons, by neutrals)
• The detailed calculation of emission lines
  
  • the statistical equilibrium for the excited states: general problem
  • collisionally excited lines, recombination lines
  • the atomic parameters
• Optically thick continua and lines
  • the radiative transfer problem
  • optically thick radio continuum
  • optically thick lines: escape probability, Sobolev approximation.
• Recipes for calculating the cooling function
  • coronal equilibrium and isochoric cooling functions
  • other parametrized and tabulated cooling functions

Required reading:

• The ionisation and excitation state of stellar outflows, by Alex Raga
  

Suggested reading:

• Measurement of physical conditions is stellar jets, by Pat Hartigan
  
  
  

Inversion of observations (Catherine Dougados, LAOG)

Summary:

• Deriving model-independent excitation conditions for the atomic gas
  • electronic density diagnostics
  • temperature diagnostics
  • BE99 technique: Te,xe from optical line ratios
  • measure of Fe depletion and dust fraction in the jet
  • limitations and uncertainties
• Derivation of excitation conditions from shock models
  • indication for shock excitation in stellar jets
  • derivation of npreshock, Vshock, Bshock
• Derivation of mass-loss rates
  • from luminosity or from nH estimates
  • under shock or volume emission
  • comparison of the different methods
• Projection and convolution effects
  • derivation of inclination angle and true space velocities
  • measure of jet transverse widths: effects of the psf
  • measure of jet rotation: true Vphi
  • biases introduced on derived jet excitation conditions

Suggested reading:

• Constraints on accretion-ejection structures in young stars, by Sylvie Cabrit.
• IR spectroscopy of jets from YSOs: diagnostics and HAR observations
• Measurement of Physical Conditions in Stellar Jets