Transcription of 1 Solutions in cylindrical coordinates: Bessel functions
{{id}} {{{paragraph}}}
Bessels 20201 Solutions in cylindrical coordinates: Bessel functionsLaplace s equation in cylindrical coordinates is:1 +1 1 + 2 z2=0 Separate variables: Let =R( )W( )Z(z).Then wefind:1R R +1W 2 2W 2+1Z 2Z z2=0 The last term is a function ofzonly, while the sum of thefirst two terms is afunction of and only. Thus we take each part to be a constant 2Z z2=k2 Zand the Solutions areZ=e kzThis is the appropriate solution outside of a charge distribution, say above aplane, ( 0asz ),or inside a cylinder with grounded walls andnon-zero potential on one remaining equation is:1R R +1W 2 2W 2+k2=0 Now multiply through by 2: R R +k2 2+1W 2W 2=0 Here the last term is a function of only and thefirst two terms are functionsof only.
To see that this equation is of Sturm-Liouville form, divide through by ρ: ∂ ∂ρ ρ ∂R ∂ρ +k2ρR − m2 ρ R =0 (1) Now we have a Sturm-Liouville equation (slreview notes eqn. 1) with f (ρ)=ρ, g(ρ)=m2/ρ, eigenvalue λ= k2 and weighting function w(ρ)=ρ. Equation (1) is Bessel’s equation. The solutions are orthogonal functions ...
Domain:
Source:
Link to this page:
Please notify us if you found a problem with this document:
{{id}} {{{paragraph}}}