Method for ascertaining a magnetic field of at least one magnetic coil unit of a magnetic resonance apparatus, magnetic resonance apparatus and computer program product

An apparatus for ascertaining a magnetic field of at least one magnetic coil unit, the apparatus comprising:

• a magnetic coil unit configured to generate the magnetic field, the magnetic coil unit comprising a main magnet for generating a main magnetic field, a gradient coil unit for generating a gradient magnetic field, or the main magnet and the gradient coil unit;
• a magnetic field sensor unit comprising at least one magnetic field sensor configured to detect a plurality of magnetic field vectors at different positions in the magnetic field, wherein each magnetic field vector of the plurality of magnetic field vectors describes a strength and a direction of the magnetic field at the respective position;
• and
• a processor configured to:
• ascertain the magnetic field based on the plurality of magnetic field vectors, the ascertainment of the magnetic field comprising ascertainment of a model of a vector field;
• and
• adjust the generation of the magnetic field based on the ascertained magnetic field, reconstruct magnetic resonance signals taking the ascertained magnetic field into account, or adjust the generation of the magnetic field based on the ascertained magnetic field and reconstruct the magnetic resonance signals taking the ascertained magnetic field into account,
• wherein the ascertainment of the magnetic field comprises decomposition of the model of the vector field into separate submodels.

In a non-transitory computer-readable storage medium that stores instructions executable by a programmable evaluation unit to ascertain a magnetic field of at least one magnetic coil unit of a magnetic resonance apparatus, the instructions comprising:

• generating the magnetic field by the at least one magnetic coil unit comprising a main magnet for generating a main magnetic field, a gradient coil unit for generating a gradient magnetic field, or the main magnet and the gradient coil unit;
• detecting a plurality of magnetic field vectors at different positions of the magnetic field by a magnetic field sensor unit comprising at least one magnetic field sensor, wherein each magnetic field vector of the plurality of magnetic field vectors describes a strength and a direction of the magnetic field at the respective position;
• ascertaining the magnetic field based on the plurality of magnetic field vectors, the ascertaining of the magnetic field comprising ascertaining a model of a vector field;
• and
• adjusting the generating of the magnetic field based on the ascertained magnetic field, reconstructing magnetic resonance signals taking the ascertained magnetic field into account, or the adjusting and the reconstructing,
• wherein ascertaining the magnetic field comprises decomposing the model of the vector field into separate submodels.