Ay 121: Radiative Processes

Instructor: S. R. Kulkarni, 1030-1200 (Tuesday & Thursday)

My goal is to follow the book closely. However, I will be adding some additional material (noted as SRK notes). In some cases, I will provide the notes by the way of a link to a pdf file.

As an observer I find myself to refresh undergraduate physics now and then. The classic book on E&M by Purcell has now been vastly revised (Purcell & Morin). I am frequently reaching to it to brush up on undergrad physics and Schaum series to brush up on those rusty knowledge of vectors, differential geometry...

You are expected to check the on-line syllabus and do the preparatory work ahead of the class.

There are really some very good courses on YouTube now. I will use this spot to list interesting courses.
There is a separate class on fluids. We will be making use of some aspects of fluid mechanics. I found the Introductory talks on Fluid Mechanics by Professor Cimbala, PSU, to be helpful.

Homeworks will be assigned every week and due 7 days later (COB). The final exam will be an oral exam with questions given to the class 2 weeks in advance. You will be asked five questions (at random) from this set. The exam will last up to an 1 hour. Homeworks will be given 2/3 weight with the remaining 1/3 for the final exam. During mid-terms (the week is TBD) we will have a short (30 minute) oral exam in lieu of a homework. It is meant to make students familiar with the framework of oral exams.

1. September 30
   
   • Introductory talk stressed the importance of remembering basic constants, the value of "pre-computing", and the benefits of making order of magnitude estimates. [SRK Notes]
   • Mandel's semi-classical theory of detection [SRK notes]
   • Spectral Flux Density (Jansky, magnitude, Rayleigh)
   • nu-fnu [SRK notes]
   Students: I covered nu-fnu and Mandel's theory quite rapidly. Please read through and, we can, at your request, briefl review at the next class.

2. October 2
   Students: review Einstein A & B coefficients and be in a position to derive Planck's brightness formula.
   • Intensity and its moments (Ch 1.3)
   • Radiative Transfer (Ch 1.4)
   • Blackbody radiation (clasical & QM; Ch 1.5)
   • Einstein A & B coefficients. Brightness temperature (Ch 1.6).
   • Homework

3. October 7
   Students: Please review Maxwell's equations and also review vector algebra (curl, del, grad and all that)
   • Poynting Vector (Ch 2.1)
   • EM waves in vaccum (Ch 2.2)
   • Introduction to Fourier transform, Power Spectrum (2.3) [SRK notes]
   • Homework 2

4. October 14
   Students: Please consult your old textbooks and become familiar with vector potential for magnetic field. Review Poisson's equation and Green's function.
   • Radiation from moving charges. Electromagnetic potentials (Ch 2.5).
   • Linenard-Wiechart potential (Ch 3.1).
   • Velocity & Acceleration fields (Ch 3.2).
   For the curious student: Gauge selection  |  Poisson's Equation  |  History of Gauge Choices.

5. October 16
   
   • Larmor Formula & Dipole approximation (Chapter 3.3)
   • Thompson scattering (Chapter 3.4)
     
   • Homework 3

6. October 21
   Students: Beware of different ways to define B-coefficients. See notes by R. C. Hilborn.
   • Radiation Reaction (3.4)
   • Classical view of line Radiation. Oscillator strength (3.5)
   • Oscillator strength (quantum).
   • Two-body atom with collisions (critical density).
   SRK notes |  The story of nebulium

7. October 23
   Students: please brush up relativity, including 4-vectors, contravariant, covariant, summation and tensor algebra.
   • 4.1 (Time dilation, length contraction, Doppler,Beaming)
   • 4.2 (4-vectors; Co- and contra-variant vectors; Proper time)
     "Co is low and that is all you need to know!"
   • 4.3 (4-velocity, 4-wave vector)
   • Homework 4
   Relativistic beaming (gif animation)
   

8. October 28
   
   • 4.3,4.4 (cursory review of tensors; E, B transformation))
   • 4.5 (physical intution of E, B field transformation)
   • 2.3 (The power spectrum of Poynting vector)
   • 4.6 (E and B fields of moving charge)
   SRK Internal notes

   Master list for mid term exam.

9. October 30
   
   • 4.7 (Four four momentum, four acceleration, Lorentz force)
   • 4.9 (Invariant Phase Volumes, Specific Intensity)
   • 4.8 (Covariant Larmor Formula)
   SRK-internal notes  |  Purcell-Relativity

10. November 4
    In advance of the class please review first three pages of SRK-internal notes. I will start the class by assuming these results.
    • 4.8 (Beam pattern of Larmor emission)
    • Introducing continuum processes of importance in astronomy
    • 5.1 (Low-velocity Bremss)

11. November 6
    In advance of class, please review page 88 and section 4.6 of R&L.
    • 5.2 (Thermal Bremss: emission)
    • 5.3 (Thermal Bremss: absorption)
    • 5.4 (Relativistic Bremss)

12. November 7 (Makeup class)
    
    • 8.1 (EM waves in plasma, dispersion relation and group velocity)
    SRK-internal notes
    What is dispersion measure?  |  Waves in Plasma |  The New SI system and commentaries

13. November 11
    Please review QM of hydrogen atom
    • 8.2 (Faraday Rotation)
    • Hydrogen atom
    SRK-internal notes
    Homework 5

14. November 13
    
    • Zeeman splitting
    • Spin-orbit coupling (fine structure)
    • Hydrogen & Alkalis
    SRK Internal  |  History of Zeeman splitting

15. November 18
    Please review QM of helium
    • Binding energy of helium atom (successive approximations)
    • Coulomb & Exchange integral
    • Beginnings of L-S coupling
    • Semi-forbidden transitions
    SRK Internal

16. November 20
    
    • Multi-electron atoms (Central field approximation)->Periodic Table
    • L-S coupling, combining valence electrons to yield terms
    • Hund's rules
    SRK internal  |  Periodic Table  |  Unix Program (2 and 3 electrons)  |  J(0->0)

17. November 25
    
    • Selection Rules
    • Hyperfine lines
    • Intro to Synchrotron Radiation (Chapter 6)
    SRK internal
    Homework 6
    Master List (Final Exam)

18. December 2
    
    • Introduction to Compton Scattering (Chapter 7)

19. December 5
    
    • Synchrotron Emission (Chapter 6)
    SRK internal