  Electromotive force is an essential quantity in dynamo theory. During a
coronal mass ejection (CME), magnetic helicity gets decoupled from the Sun and
advected into the heliosphere with the solar wind. Eventually, a heliospheric
magnetic transient event might pass by a spacecraft, such as the Helios space
observatories. Our aim is to investigate the electromotive force, the kinetic
helicity effect ($\alpha$ term), the turbulent diffusion ($\beta$ term) and the
cross-helicity effect ($\gamma$ term) in the inner heliosphere below 1 au. We
set up a one-dimensional model of the solar wind velocity and magnetic field
for a hypothetic interplanetary CME. Because turbulent structures within the
solar wind evolve much slower than this structure needs to pass by the
spacecraft, we use a reduced curl operator to compute the current density and
vorticity. We test our CME shock-front model against an observed magnetic
transient that passes by the Helios-2 spacecraft. At the peak of the
fluctuations in this event we find strongly enhanced $\alpha$, $\beta$ and
$\gamma$ terms, as well as a strong peak in the total electromotive force. Our
method allows us to automatically identify magnetic transient events from any
in-situ spacecraft observations that contain magnetic field and plasma velocity
data of the solar wind.
