6
NEWS
June 2026 ESRFnews
Engineered voids stabilise fusion
of jets and mixing Phys Rev Lett
136 145102 The phenomenon
was predicted theoretically four
decades ago but never observed
experimentally before now
These findings demonstrate that
carefully designed subsurface features
can strongly influence fluid behaviour
at material surfaces including jet
suppression the researchers say
This insight suggests new strategies
for controlling mixing in systems with
rapid pressure and density gradients
including inertial fusion
This experiment was performed
through the Shock block allocation
group a mode of community access
to the ESRF For more information
see www esrf fr CommunityAccess
Ultrafast ESRF imaging has shown
how tiny engineered voids could help
stabilise inertial confinement fusion ,
by reshaping shock waves as they pass
through matter . The results could help
improve future designs in the pursuit of
fusion as a clean energy source .
Inertial confinement fusion ( ICF )
works by compressing small capsules
of hydrogen isotopes to extreme
densities and temperatures , usually
with lasers . The process is notoriously
unstable , because powerful shock
waves tend to trigger hydrodynamic
instabilities in the capsules , causing
the materials to mix uncontrollably .
In particular , the Richtmyer –
Meshkov instability arises when a
shock wave strikes the boundary
between materials of different
densities , producing rapidly growing
jets . These instabilities can drag
impurities into the fuel , cooling it and
preventing ignition .
In the new study , Jergus Strucka at
Imperial College London in the UK
and colleagues have demonstrated
a way to suppress the Richtmyer –
Meshkov instability without
changing either the external driver
or the surface geometry of the target
itself . Instead , the team used machine
learning to design microscopic voids
beneath the corrugated surface of a
gelatine - based experimental target ,
and studied the resulting behaviour at
the ID19 beamline The experiments
required the discharge of more than
100 000 amperes through samples in
just 600 nanoseconds comparable to
several lightning strikes at once
The radiographic images up to
five and a half million per second at
ID19 showed that the engineered
voids collapse when a shock wave
passes through the samples
transforming the shock wave into
a sequence of weaker shocks and
substantially reducing the growth
“ Experiments required the
discharge of more than 100 , 000
amperes through samples in just 600
nanoseconds – comparable to several
lightning strikes at once ”
J E R G U S S T R U C K A / I M P E R I A L C O L L E G E L O N D O N
A rapid electrical
discharge through
a fusion target
coincides with
high speed internal
imagery at ID19