首页   按字顺浏览 期刊浏览 卷期浏览 Generalized parallel heat transport equations in collisional to weakly collisional plas...
Generalized parallel heat transport equations in collisional to weakly collisional plasmas

 

作者: Emad Zawaideh,   N. S. Kim,   Farrokh Najmabadi,  

 

期刊: Physics of Fluids(00319171)  (AIP Available online 1988)
卷期: Volume 31, issue 11  

页码: 3280-3285

 

ISSN:0031-9171

 

年代: 1988

 

DOI:10.1063/1.866940

 

出版商: AIP

 

数据来源: AIP

 

摘要:

A new set of two‐fluid heat transport equations that is valid from collisional to weakly collisional limits is derived. Starting from gyrokinetic equations in flux coordinates, a set of moment equations describing plasma energy transport along the field lines of a space‐ and time‐dependent magnetic field is derived. No restrictions on the anisotropy of the ion distribution function or collisionality are imposed. In the highly collisional limit, these equations reduce to the classical heat conduction equation (e.g., Spitzer and Ha¨rm or Braginskii), while in the weakly collisional limit, they describe a saturated heat flux (flux limited). Numerical examples comparing these equations with conventional heat transport equations show that in the limit where the ratio of the mean free path &lgr; to the scale length of the temperature gradientLTapproaches zero, there is no significant difference between the solutions of the new and conventional heat transport equations. As &lgr;/LT→1, the conventional heat conduction equation contains a significantly larger error than (&lgr;/LT)2. The error is found to beO(&lgr;/L)2, whereLis the smallest of the scale lengths of the gradient in the magnetic field, or the macroscopic plasma parameters (e.g., velocity scale length, temperature scale length, and density scale length). The accuracy of the flux‐limited model depends significantly on the value of the flux limit parameter which, in general, is not known. The new set of equations shows that the flux‐limited parameter is a function of the magnetic field and plasma parameter profiles.

 

点击下载:  PDF (700KB)



返 回