What is the significance of the title of Sylvia Plath's poem "Ariel"?

This is one of the more interesting poems of the 20th century. The denotation of the title is gentle, and threefold: literally, Ariel was the author's horse. The poem is a description of the author sensing power in her exhilarating helplessness, almost fallen off and clinging to Ariel's neck (the brown arc/of the neck I cannot catch). By allusion, Ariel is also the magical spirit serving Prospero, a sort of fey instrument adding richness to the idea of the horse, and perhaps making it a symbol for art. Although this is the first ociation that will capture a new reader, it is the least significant. More importantly, Ari'el means `Lion of God' in Hebrew (El is god, as in El'izabeth, oath of god, Ezeki'el, strengthened by God, etc.), and was a name for the city of Jerusalem in the Old Testament. Plath is explicit about this in line 4: `God's lioness....' I think the important sense here is the prophecy it was to be destroyed by fire-- the poem ends as a frenzied ride upon Ariel into the sun. Often commented is that this frenzy of art is what creates or fortifies identity-- the profusion of `i' sounds in the last couple of stanzas is obviously deliberate.