[1] Numerical ray tracing indicates that the in situ injection of whistler mode waves of 1 kHz to 4 kHz can be used to illuminate the inner radiation belts and slot region. These results were derived by using the Stanford VLF Ray Tracing Program to simulate sources placed at a total of six points in the inner magnetosphere: L = 1.5, L = 2.0, and L = 2.5 at two geomagnetic latitudes, the equator and a latitude of 20° along each field line. The results demonstrate that an in situ source, by varying the frequency of the injected waves, can illuminate L shells both higher and lower than the source site, with wave frequencies below (above) the local lower hybrid resonance, fLHR, moving to higher (lower) L shells. Accounting for the limitations that would be imposed by a practical antenna immersed in the magnetospheric medium restricts the radiating wave frequency, f, to 0.9 fLHR ≤ F < (fLHR + 1 kHz), and the wave normal angle at injection to no farther than 3° from the resonance cone. Even after accounting for these restrictions, it requires only three in situ sources placed at the above locations to illuminate 1.4 ≃ L ≃ 2.7, which comprises the bulk of the inner radiation belt.