How to express exp(kCos(gamma)) using spherical harmonics?

  • Thread starter vanmil
  • Start date
In summary, the formula for expanding exp(kCos(gamma)) in spherical harmonics (SH) is: exp(kCos(gamma)) = ∑<sub>l=0</sub><sup>∞</sup> ∑<sub>m=-l</sub><sup>l</sup> C<sub>l,m</sub>Y<sub>l,m</sub>(θ,φ), where C<sub>l,m</sub> and Y<sub>l,m</sub>(θ,φ) are the spherical harmonic coefficients and functions, respectively. This expansion allows for the representation of complex or periodic functions on a spherical surface, with applications in physics, astronomy, and geodesy. The SH
  • #1
vanmil
3
0
Hello all, i am looking for a relation to express exp(kCos(gamma)) in spherical harmonics. How can I express it?


thanks
 
Physics news on Phys.org
  • #2
Look in any advanced text in math physics, quantum mechanics or E&M, what you are looking for is the expansion of a plane wave in terms of spherical harmonics and Bessel functions.
 
  • #3
Thanks for your reply Dr. Transport, I want to use spherical harmonic expansions for exponential functions in a transfer matrix.
 

1. What is the formula for expanding exp(kCos(gamma)) in spherical harmonics (SH)?

The formula for expanding exp(kCos(gamma)) in SH is:
exp(kCos(gamma)) = ∑l=0m=-ll Cl,mYl,m(θ,φ), where Cl,m and Yl,m(θ,φ) are the spherical harmonic coefficients and functions, respectively.

2. What is the significance of expanding exp(kCos(gamma)) in SH?

Expanding exp(kCos(gamma)) in SH allows us to represent a complex or periodic function in terms of simpler, orthogonal functions on a spherical surface. This can have applications in fields such as physics, astronomy, and geodesy.

3. How can the SH expansion of exp(kCos(gamma)) be calculated?

The SH expansion of exp(kCos(gamma)) can be calculated using numerical methods such as the Fast Multipole Method (FMM) or the Discrete Spherical Harmonic Transform (DSHT). These methods involve breaking down the function into smaller, localized components and calculating their respective spherical harmonic coefficients.

4. What are some limitations of expanding exp(kCos(gamma)) in SH?

One limitation is that the SH expansion is only valid for functions on a spherical surface, so it may not be applicable to all types of data. Additionally, the accuracy of the expansion may decrease as the degree and order of the SH increases, and the computation time can be significant for large datasets.

5. Can exp(kCos(gamma)) be expanded in SH for non-constant values of k?

Yes, exp(kCos(gamma)) can be expanded in SH for non-constant values of k. This would result in a time-varying spherical harmonic expansion, which can have applications in fields such as climate modeling and signal processing. However, the computation and interpretation of the coefficients may be more complex compared to the constant k case.

Similar threads

  • Calculus and Beyond Homework Help
Replies
7
Views
1K
  • Calculus and Beyond Homework Help
2
Replies
47
Views
2K
  • Calculus and Beyond Homework Help
Replies
7
Views
700
  • Calculus and Beyond Homework Help
Replies
5
Views
2K
  • Calculus and Beyond Homework Help
Replies
2
Views
771
  • Calculus and Beyond Homework Help
Replies
3
Views
1K
  • Calculus and Beyond Homework Help
Replies
6
Views
1K
  • Calculus and Beyond Homework Help
Replies
5
Views
1K
  • Calculus and Beyond Homework Help
Replies
1
Views
1K
Replies
4
Views
698
Back
Top