天文達人

撰寫者：韋心潔

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pro maxwell_boltzmann

;the program is the equation of maxwell_boltzmann

;written by Ruth Wei



m=1.67e-27       ;the mass of electron

k=1.38e-23       ;boltzmann constant

N=1.e5           ;mole

T1=20000.
T2=30000.
T3=40000.


v=findgen(400)*200


Nv1=N*(m/(2.*!pi*k*T1)^(3./2.))*(4.*!pi*v^2.)*exp((-m*v^2.)/(2.*k*T1))
Nv2=N*(m/(2.*!pi*k*T2)^(3./2.))*(4.*!pi*v^2.)*exp((-m*v^2.)/(2.*k*T2))
Nv3=N*(m/(2.*!pi*k*T3)^(3./2.))*(4.*!pi*v^2.)*exp((-m*v^2.)/(2.*k*T3))


;set_plot,"ps"

;device,filename="C:\Documents and Settings\Ruth\�ୱ\maxwell_boltzmann.ps

meanings = ['T=20000 K', 'T=30000 K', 'T=40000 K']

lines = [1,3,4]

plot,v,Nv1, linestyle=1, thick=1, title="maxwell velocity",xtitle="m/s", ytitle="mole/(m/s)"
oplot,v,Nv2, linestyle=3, thick=3
oplot,v,Nv3, linestyle=4, thick=4

;LEGEND, linestyle=lines, meanings, /top, /right;, Columns=8 ;, linestyle=lines
;LEGEND, linestyle=lines, meanings, /top, /right;, Columns=8 ;, linestyle=lines
xyouts, 5.e4, 1.e14, '........ 20000K'
xyouts, 5.e4, 9e13, '_._._._.30000K'
xyouts, 5.e4, 8e13, '_..._...40000K'

;device,/close

print,'ok'

end

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