Cadenza 1:
Using the open A string as a base, keep playing it in between (intermittently*), while playing various double stops (sixths, fourths, thirds, seconds), increasing in tempo and volume, and going into very high positions (about three bowed octaves). At the climax, change to enharmonic single runs (loud, briliant, fast) and bring these organically to the following goal:
Cadenza 2:
High and highest, quiet and sweet long whistling harmonics (also artifical harmonics, maybe even double stops) ad libitum for as long as the tension of both player and audience can be held.
I wonder if the single run refers to runs that are not double stops?
* (I have edited in the "intermittent" a day later, since the word did not occur to me before.)