  Several low-power kiloparsec-scale jets in nearby radio galaxies are known
for their synchrotron radiation extending up to optical and X-ray photon
energies. Here we comment on high-energy gamma-ray emission of one particular
object of this kind, i.e. the kiloparsec-scale jet of M 87 radio galaxy,
resulting from comptonization of the starlight photon field of the host galaxy
by the synchrotron-emitting jet electrons. In the analysis, we include
relativistic bulk velocity of the jet, as well as the Klein-Nishina effects. We
show, that upper limits to the kiloparsec-scale jet inverse-Compton radiation
imposed by HESS and HEGRA Cherenkov Telescopes - which detected a variable
source of VHE gamma-ray emission within 0.1 deg (~30 kpc) of the M 87 central
region - give us an important constraint on the magnetic field strength in this
object, namely that the magnetic field cannot be smaller than the equipartition
value (referring solely to the radiating electrons) in the brightest knot of
the jet, and most likely, is even stronger. In this context, we point out a
need for the amplification of the magnetic energy flux along the M 87 jet from
the sub-parsec to kiloparsec scales, suggesting the turbulent dynamo as a
plausible process responsible for the aforementioned amplification.
