title: Observation of inertial energy cascade in interplanetary space plasma.
abstract: Direct evidence for the presence of an inertial energy cascade, the most characteristic signature of hydromagnetic turbulence (MHD), is observed in the solar wind by the Ulysses spacecraft. After a brief rederivation of the equivalent of Yaglom's law for MHD turbulence, a linear relation is indeed observed for the scaling of mixed third-order structure functions involving Elsässer variables. This experimental result firmly establishes the turbulent character of low-frequency velocity and magnetic field fluctuations in the solar wind plasma.
authors.affiliation: Licryl Regional Laboratory - INFM/CNR, Ponte P. Bucci, Cubo 33C, 87036 Rende (CS), Italy.
authors.forename: L
authors.initials: L
authors.lastname: Sorriso-Valvo
authors.forename: R
authors.initials: R
authors.lastname: Marino
authors.forename: V
authors.initials: V
authors.lastname: Carbone
authors.forename: A
authors.initials: A
authors.lastname: Noullez
authors.forename: F
authors.initials: F
authors.lastname: Lepreti
authors.forename: P
authors.initials: P
authors.lastname: Veltri
authors.forename: R
authors.initials: R
authors.lastname: Bruno
authors.forename: B
authors.initials: B
authors.lastname: Bavassano
authors.forename: E
authors.initials: E
authors.lastname: Pietropaolo