FI226: Magnetic trap

Simulation of the magnetic field generated by a anti-helmholtz coil done as a homework of FI226 (IFGW-Unicamp).

Python scripts/modules:

• coil_utils module
• coilSimulation_exact module
• coilSimulation_real module

coil_utils.py module is intended to calculates the magnetic field of coils. The parameters of the function are illustrated in fig. 1 and 2 for an arbitrary current loop and for anti-helmholtz coil, respectively.

coilSimulation_exact.py and coilSimulation_real.py simulates the helmholtz coil given some parameters.

Fig 1.

Fig 2.

Figures 3 and 4 shows the simulated results of a anti-helmholtz coil together with measured data using a gaussimeter. The coils had 150 turns and R=2.5 cm, D=2.45 cm, I=1 A. The default values of coilSimulation_exact.py and coilSimulation_real.py reproduce these results.

Fig 3.

Fig 4.

The derivative of measured data does not seem really good due to the small number of measured points. To correct that we may artificially increase the number of measured by. Two methods are presented. The script /data/comparisson.py reproduce the results below.

1. To interpolate the data, then average each 100 point to smooth the curve:

Fig 5.

Fig 6.

2. Fitting the data using a 5 order polynomial.

Fig 7.

Fig 8.