scholarly journals Transformation of the integral using Hylleraas coordinates in N-dimensions

2006 ◽  
Vol 84 (9) ◽  
pp. 857-859
Author(s):  
Soma Mukhopadhyay ◽  
Ashok Chatterjee

The integral ∫ F(r, r′, |r–r′|) dr dr′ where r and r′ are N-dimensional position vectors can be transformed into a simple three-dimensional integral using Hylleraas coordinates. A simple derivation of this result is presented. PACS Nos.: 31.15.–p; 31.15.Ja; 03.65.–w

2021 ◽  
Vol 87 (2) ◽  
Author(s):  
P. Kim ◽  
R. Jorge ◽  
W. Dorland

A simplified analytical form of the on-axis magnetic well and Mercier's criterion for interchange instabilities for arbitrary three-dimensional magnetic field geometries is derived. For this purpose, a near-axis expansion based on a direct coordinate approach is used by expressing the toroidal magnetic flux in terms of powers of the radial distance to the magnetic axis. For the first time, the magnetic well and Mercier's criterion are then written as a one-dimensional integral with respect to the axis arclength. When compared with the original work of Mercier, the derivation here is presented using modern notation and in a more streamlined manner that highlights essential steps. Finally, these expressions are verified numerically using several quasisymmetric and non-quasisymmetric stellarator configurations including Wendelstein 7-X.


2013 ◽  
Vol 52 (4) ◽  
pp. 546 ◽  
Author(s):  
Xiao Xiao ◽  
Bahram Javidi ◽  
Manuel Martinez-Corral ◽  
Adrian Stern

1999 ◽  
Vol 14 (29) ◽  
pp. 4549-4574 ◽  
Author(s):  
C. R. GATTRINGER ◽  
S. JAIMUNGAL ◽  
G. W. SEMENOFF

We construct an algebraic representation of the geometrical objects (loop and surface variables) dual to the spins in 2 and 3D Ising models. This algebraic calculus is simpler than dealing with the geometrical objects, in particular when analyzing geometry factors and counting problems. For the 2D case we give the corrected loop expansion of the free energy and the radius of convergence for this series. For the 3D case we give a simple derivation of the geometry factor which prevents overcounting of surfaces in the intrinsic geometry representation of the partition function, and find a classification of the surfaces to be summed over. For 2 and 3D we derive a compact formula for 2n-point functions in loop (surface) representation.


2011 ◽  
Vol 19 (11) ◽  
pp. 2805-2811 ◽  
Author(s):  
焦小雪 JIAO Xiao-xue ◽  
赵星 ZHAO Xing ◽  
杨勇 YANG Yong ◽  
方志良 FANG Zhi-liang ◽  
袁小聪 YUAN Xiao-cong

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