... After allowing for 30% uncertainty in the SWCX emission and subtracting it from the observational data, we estimate that the flux of cosmic background for the CDFN in the O vii K , K , and O viii Ly lines totals 5.8 ± 1.1 photons s-1 cm-2 sr-1 (or LU). ... Models of this SWCX require as inputs the speed and density of the solar wind ions and the interstellar neutrals over the line of sight (LOS) through the heliosphere. ... These lines are shown in the example model SWCX spectrum of Figure 5. ...