We start where we use an inflaton value due to use of a scale factor miñ a a t γ . Also we use How to cite this paper: Beckwith, A.W. (2018) How to Determine a Jump in Energy Prior to a Causal Barrier, with an Attendant Current, for an Effective Initial Magnetic Field. In the Pre Planckian to Planckian Space-Time. Journal of High Energy Physics, Gravitation and Cosmology, 4, 323-353. Journal of High Energy Physics, Gravitation and Cosmology g m c v c U c E = − = − , so as to come up with a post New-tonian approximation result for a magnetic field. We compare this magnetic field, as far as the Inflaton magnetic field, and use it to come up with observations with regards to the phenomenology of gravity in Pre Planckian to Planckian regime limits. We close, then with the observation given in Appendix H, of the inhomogeneity of Pre Planckian-to Planckian space time as a necessary condition for a Gravi-Magnetic field. We also reference an Appendix I, which does a summary of a 5 th force calculation, and we then compare those results, with our temporary results of a Gravi Magneitc field, as we have tried to start up as a future works project.