Abstract
The Coulomb logarithm is a fundamental plasma parameter which is commonly derived within the framework of the binary collision approximation. The conventional formula for the Coulomb logarithm, λ=ln Λ, takes into account a pure Coulomb interaction potential for binary collisions and is not accurate at small values (λ<10). However, a more exact Fokker–Planck equation was recently presented by Li and Petrasso which is accurate at small Coulomb logarithm values (λ≳2) [Phys. Rev. Lett. 70, 3063 (1993)]. This theory and computer simulations which are accurate for small Coulomb logarithm values provide the motivation for a more precise evaluation of the Coulomb logarithm. In the present work, the Coulomb logarithm is evaluated more precisely by using a cutoff Coulomb interaction potential. The result is compared to an exact numerical evaluation of the Coulomb logarithm which considers a screened Coulomb interaction potential. Fits to the numerical results are also provided. The fitted formula λ=ln(0.6 Λ) is recommended for most applications providing values within 4% of the exact numerical values for λ≳2. This formula is easily implemented by using 0.6λD in place of λD (the Debye length) in the conventional formula for the Coulomb logarithm.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
