Task: Text Categorization
Input (English): In antenna theory it can be obtained from the superposition of one turn of the helical antenna translated along the z-axis. Its physical significance was demonstrated in an experiment in which a shielded solenoid produced interference in an external (*) field-free region. Since its divergence has no physical significance, the Lorenz gauge can be used to separate it from the electric scalar potential and its nature was elucidated in the Aharonov-Bohm experiment. For 10 points, name this vector field with a curl that equals the magnetic field.
Output (English): Science