5.3 Tailoring guidelines

a. While the IGRF 10 model should normally be used for internal fields, a lowfidelity dipole model (using aligned, eccentric or tilted dipoles as appropriate) may suffice for some engineering applications_.

b. For the external field, the recent Tsyganenko 2001 [RD.98] and 2004 [RD.99] models may be used instead of the reference models defined in clause 5.2.2.

NOTE Most engineering applications do not need the externalsource model augmentation of these later Tsyganenko models. These are only useful for certain scientific magnetospheric missions, for instance if data on high latitude or high altitude variability of the fields with respect to local time and solargeomagnetic activity was important.