leucosphere

From leuco- +‎ -sphere.

leucosphere (plural not attested)

1. (astronomy, obsolete, rare) The inner corona.

The name was proposed in the 1880s, but never gained popularity in astronomy. There seems to be no common word for it, though "inner solar corona" is quite widespread.

• “leucosphere”, in Webster’s Revised Unabridged Dictionary, Springfield, Mass.: G. & C. Merriam, 1913, →OCLC.