  The proximity induced pair potential in a topological
insulator-superconductor hybrid features an interesting superposition of a
conventional spin-singlet component from the superconductor and a spin-triplet
one induced by the surface state of the topological insulator. This
singlet-triplet superposition can be altered by the presence of a magnetic
field. We study the interplay between topological order and superconducting
correlations performing a symmetry analysis of the induced pair potential,
using Green functions techniques to theoretically describe ballistic junctions
between superconductors and topological insulators under magnetic fields. We
relate a change in the conductance from a gapped profile into one with a
zero-energy peak with the transition into a topologically nontrivial regime
where the odd-frequency triplet pairing becomes the dominant component in the
pair potential. The nontrivial regime, which provides a signature of
odd-frequency triplet superconductivity, is reached for an out-of-plane
effective magnetization with strength comparable to the chemical potential of
the superconductor or for an in-plane one, parallel to the
normal-superconductor interface, with strength of the order of the
superconducting gap. Strikingly, in the latter case, a misalignment with the
interface yields an asymmetry with the energy in the conductance unless the
total contribution of the topological surface state is considered.
