Changes between Version 8 and Version 9 of u/erica/JeansInstability


Ignore:
Timestamp:
06/21/13 11:50:35 (11 years ago)
Author:
Erica Kaminski
Comment:

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  • u/erica/JeansInstability

    v8 v9  
    4545[[latex($\rho_1 = \cos(kx)e^{^+ _-\omega t}$)]]
    4646
    47 Thus, the perturbation takes on a form that is oscillatory in x and exponential in time. To get the critical length scale (aka Jeans length) for the oscillations, we write the oscillatory condition
     47Thus, the perturbation takes on a form that is oscillatory in x and exponential in time.
     48
     49= The Jeans Length =
     50
     51To get the critical length scale (aka Jeans length) for the oscillations, we write the oscillatory condition
    4852
    4953[[latex($C_s^2 k^2 > 4 \pi G \rho_0$)]]
     
    5862
    5963
    60 
     64= Unstable Modes =
    6165
    6266What we'd like to do now is determine, for which frequencies is the perturbation ''unstable'' (exponentially growing). In order to determine this we can rewrite [[latex($\omega$)]] into a more intuitive form.
     
    8791[[latex($\tau = \frac{1}{\Gamma}$)]]
    8892
     93= High lambda limit, i.e. pressure-less collapse, i.e. uniform collapse =
     94
    8995