Transforming synthesised traces on the vxvxB axis to a star-shape antenna layout¶

When using the origin library provided with template synthesis, the origin showers are simulated on the \(\vec{v} \times \vec{v} \times \vec{B}\) axis. This means that the synthesised traces are also generated on this axis. However, in many cases, the user might want to have traces on a star-shape antenna layout in the shower plane.

To achieve this, we provide the function smiet.numpy.utilities.reconstruct_starshape_from_vxvxB(), which simply takes the synthesised traces on the \(\vec{v} \times \vec{v} \times \vec{B}\) axis and copies them to the desired star-shape antenna positions, applying a rotation in the shower plane. This approach is possible since we expect the geomagnetic and charge-excess emission to be rotationally symmetric in strength. The number of arms can also be chosen freely, with the default being 8 arms (i.e. a star shape).

Example (NumPy)¶

from smiet.numpy.utilities import reconstruct_starshape_from_vxvxB

synthesis = TemplateSynthesis()
# .....
# perform synthesis with origin shower on vxvxB arm only
# .....
synthesised_geo_vvB, synthesis_ce_vvB = synthesis.map_template(...)

# we take only the y-positions of the antennas, since the origin shower
# is simulated on the vxvxB axis (i.e. x=0)
ant_positions_vvB = synthesis.antenna_information["position_showerplane"][:,1]

# reconstructing to star-shape antenna layout
synthesised_geo_starshape, synthesised_ce_starshape = reconstruct_starshape_from_vxvxB(
    synthesised_geo_vvB,
    synthesis_ce_vvB,
    ant_positions_vvB,
    number_of_arms = 8 # number of arms in the star-shape layout
)

A similar implementation is provided in the JAX implementation of SMIET, which can be imported from smiet.jax.utilities.utilities.reconstruct_star_from_vxvxB().

Example (JAX)¶

from smiet.jax.utilities import reconstruct_starshape_from_vxvxB

synthesis = TemplateSynthesisJAX()
# .....
# perform synthesis with origin shower on vxvxB arm only
# .....
synthesised_geo_vvB, synthesis_ce_vvB = synthesis.map_template(...)

# we take only the y-positions of the antennas, since the origin shower
# is simulated on the vxvxB axis (i.e. x=0)
ant_positions_vvB = synthesis.ant_positions_vvB[:,1]

# reconstructing to star-shape antenna layout
synthesised_geo_starshape, synthesised_ce_starshape = reconstruct_starshape_from_vxvxB(
    synthesised_geo_vvB,
    synthesis_ce_vvB,
    ant_positions_vvB,
    number_of_arms = 8 # number of arms in the star-shape layout
)