
#1
Nov2607, 10:32 AM

P: 9

Hello everybody!
I have some trouble determinating the magnetic field generated by a circular loop of current. I'd use it as an approximation for the poloidal field in a Tokamak (field generated by the current in the plasma). I tried using BiotSavard's Law but I'm getting stuck... I hope to get an answer soon greets ramses P.S. I'm not looking for the field in the middle of the current loop, I need the whole description vector field. 



#2
Nov2607, 12:41 PM

Sci Advisor
PF Gold
P: 2,020

This is presented in all standard E&M books. Take a look at
Jackson, Classical Electrodynamics or Smythe, Static and Dynamic Electricity 



#3
Nov2607, 12:59 PM

P: 9

Thanx, but I think I'll have some difficulties getting those books... I'm in the italian speaking part of switzerland, but I'll give a try to my school library.
If there is some kind of electronic version on this specific topic, could someone link it plaese? 



#4
Nov2607, 02:05 PM

Sci Advisor
PF Gold
P: 2,020

Magnetic field generated by a circular current loop
Oh, how fun! Well, the result is quoted here without derivation
http://www.netdenizen.com/emagnet/of...oopoffaxis.htm 



#5
Nov2607, 07:32 PM

P: 1

I've been looking for the same thing  offaxis magnetic field strength at a distance from the source of the field. All my university physics texts give the onaxis derivation (or at least binomial approximation), but hold short of offaxis derivations for B. I contacted Eric Dennison at netdenizen.com (see previous post by Marcus!). He thinks he has a derivation. I am hoping to hear from him shortly. I'm probably as bad off as ramses728, up in the north woods of Wisconsin, USA. The nearest source for these texts is about 250300 km away.




#6
Nov2707, 10:21 AM

P: 9

I understand your situation Istookey, no one here where I live has some real good clue how to solve this problem. I tried some ways through the biot savard law but had not much luck... And just having those formulas written does not help me really much how to get there... I'll try again now see if i get something out of it.
If you Eric Dennison from netdenizen.com replies let me know. greets ramses 



#7
Dec2907, 10:08 PM

P: 4

I believe what you are looking for is extensively analyzed here:
http://plasmalab.pbwiki.com/f/bfield.pdf 



#8
Jan308, 09:03 PM

P: 127

Oh my... I've been searching for that field for years! Thank You!




#9
Jan408, 07:44 AM

P: 455

There is a simpler treatment using Legendre polynomials in the book "Classical Electromagnetism" by Franklin. It also treats the offaxis magnetic field of a solenoid or bar magnet.




#10
Nov1808, 04:28 AM

P: 3





#11
Nov1808, 04:29 AM

P: 3

without Legendre polynomials or Greens functions or elliptical functions usage ,,,u cant solve this problem analytically,,,,,,,better try numerical methods for a simple treatment.....




#12
Dec908, 07:45 AM

P: 1

For a new derivation, see:
http://dx.doi.org/10.1088/01430807/27/5/N01 



#13
Dec908, 11:25 AM

Sci Advisor
P: 1,250

That could have been proven more easily using spherical harmonics. 


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