Trying to give you a simple answer based on analytical arguments (formula), I realized that the expressions given above do not refer to any arbitrary point within the circle other than the center. The expression for any point however is not simple, as can be seen here View attachment 154018, it requires calculation by numerical integration, so I insist that you consider performing experiments with the aid of simulation tools for field solving.
Yes, weakest on the center line. In so far the field calculation over the full operation volume can be bypassed if you are only interested on the minimal field strength.Are you now saying field is weakest at the center of the solenoid. I assume you mean since it is the farthest point from the coils looking inward. Or is there something I'm missing.
Yes, weakest on the center line. In so far the field calculation over the full operation volume can be bypassed if you are only interested on the minimal field strength.
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Field becomes rather uniform, but maximum Bz is only about 0.2T due to the long coil. Total NI = 450*50
View attachment 154021
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The previous coil had only 120 mm length. One more with 160 mm, same NI. Bz, max reduces to 0.16T
View attachment 154022
Although the coil dimensions are not fulfilling the "long solenoid" criterion length > 100*radius, the respective field strength value B = µ*NI/L can be used as a first estimation. Check with last two examples. Making the coil longer gets you closer to the long coil estimation. It gives 0.067 for NI=15000, L=0.28m
Yes, reduced NI + increased coil length compared to previous case. With sufficient coil length, the coil diameter doesn't affect the field strength.
Sorry, I see that I misunderstood your coil dimension specs. "Width" means diameter and "Height" coil length?
The coils with larger diameter achieve lower field strength. Use a geometry where the average distance of windings to coil center point is minimal.
Within your constraints you should consider a small diameter (5cm) Helmholtz coil configuration augmented with some neodymium magnets (N52 or better) placed along the axis. Or with an additional closed loop iron core solenoid with a commensurate air gap aligned with the helmholtz structure.
Otherwise one or another of your contraints will trip you up - wire dia, max current, heat dissipation, power supply capability etc etc.
Without your imposed constraints it is easy to make a uniform >=4 Tesla magnetic field.
I already did, as reported the center point field strength is lower, only 0.244 T. Thus I thought the simulation details are not so interesting.
View attachment 154054
An older version of QuickField
So when you write 'same current' do you mean 50 amps?
And when you say it is 'pulsed', what duty cycle & frequency do you mean?
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