Electrodynamics and Radiative Processes I

Semester I, Term I of the IUCAA-NCRA Graduate School 2015-2016

The final exam will be on 28th September, 1:45pm-3:45pm in the NCRA Lecture Hall. The exam will be open notes exam.

Textbooks followed

Important Information

• This is a 14 lecture (1h each) course.
• The classes will start 2015, Aug 04. The classes will be on Tuesdays and Thursdays at 10-11am.
• There will be no class during the week 2015, Aug 24-28.
• There will be mini assignments given during every class. You are requested to submit them in the next class. They will carry 40% weight.
• Final exam will be open notes exam. The exam will carry 60% weight.
• There will be an extra class on 12th September, Saturday starting at 10:30am. The class will be for 1.5 hours duration.
• The class on 15th September will also be of 1.5 hour duration.
• The last class of this course will be on 16th September, Wednesday at 2:30pm. This will give enough time for students to prepare for the exam.

Syllabus

• Lecture 1, 2015 Aug 04: Elementary properties of radiation, Radiative flux, Specfic intensity and its moments, Specfic energy density, Radiative transfer equation.
  

  Mini assignment:

  1:) Solve the Radiative transfer equation

  dIν⁄dτ=

  -Iν+Sν

• Lecture 2, 2015 Aug 06: Equation of Radiative transfer and its interpretation, Thermal and Blackbody emission, Planck's spectrum, Characteristic Temperatures, Einstein's coefficients.
  

  Mini assignment:

  1:) Using Laws of Thermodynamics, prove that for thermal radiation, u=σT⁴
  2:) Estimate the number of photons in a volume of 1 cm³ at room temperature (300 K).
  3:) Derive Planck's law for per unit wavelength interval , i.e. B_λ(T).
• Lecture 3, 2015 Aug 11: Review of Electromagnetic Theory: Maxwell's Equations, Electromagnetic Potentials, Plane Electromagnetic waves, Radiation Spectrum, Polarization and Stokes Parameters
  

  Mini assignment:

  1:) Wrtie Maxwell's Equations using Electromagnetic Potentials.
• Lecture 4, 2015 Aug 13: Electromagnetic Radiation from moving charges, Lienard-Wiechart Potentials, Velocity and radiation fields, Larmor's Formula, Dipole Approximation, Multipole Expansion, Thomson Scattering
  

  Mini assignment:

  1:) Derive expression for Lienard-Wiechart Potentials.
• Lecture 5, 2015 Aug 18: Brief review of four-vectors, Lorentz transformations, tensor analysis, co-variance in Electromagnetism, Relativistic Larmour's formula
  

  Mini assignment:

  1:) Review the concepts of Lorentz transformations, four-vectors and tensors 2:) Derive the expression for four-velocity. Show that scalar product of four velocity is U^μ U_μ=-c².
• Lecture 6, 2015 Aug 20: Fields of a uniformly moving charge, Bremsstrahlung, Thermal and non-thermal Bremsstrahluncg, free-free absorption, Relativistic Bremsstrahlung
  
• Lecture 7, 2015 Sep 01: Basics of Synchrotron emission, Astrophysical sources with synchrotron emission
  

  Mini assignment:

  1:) Pick your favourite Astrophysical source which emit radiation via Synchrotron mechanism and write about it (Use your creativity here)!
• Lecture 8, 2015 Sep 03: Beaming in synchrotron radiation, Angular distribution of emitted and radiated power, Emission from relativistic particles, Qualitative treatment of shape of synchrotron radiation and spectral index
  

  Mini assignment:

  1:) Determine the angular distribution of the received power in extreme relativistic limit.
• Lecture 9, 2015 Sep 08: Detailed derivation of synchrotron spectrum due to a single electron, due to ensemble of electrons, Polarization of synchrotron radiation, Synchrotron self-absorption.
  
• Lecture 10, 2015 Sep 10: Compton Scattering, Inverse Compton scattering, classical treatment, Power emitted in Inverse Compton scattering (Also refer to High Energy Astrophysics, Volume I by Longair)
  

  Mini assignment:

  1:) Using the conservation of four-momentum for a photon scattering off an electron at rest, derive the relation between initial and final energy of photon, initial and final wavelength of photon.
• Lecture 11, 2015 Sep 10, 1.5hr: Synchrotron Self-Comptonized Emission, Inverse-Compton Limit for Synchrotron sources, Inverse-Compton spectra for single scattering, Compton Y-parameter, Brief description of Kompaneets Equation.
  
• Lecture 12, 2015 Sep 15, 1.5hr: Plasma Effects, Dispersion Smearing, Faraday Rotaion, Scintillation Effects (Qualitative), Cherenkov Radiation, Razin Effect.
  
• Lecture 13, 2015 Sep 16: Acceleration Processes, Line Broadening mechanisms - Doppler broadening, Natural Broadening, Collisional Broadening.