Aiming breakeven for nuclear fusion energy needs a more than 1000 times higher fusion gain. This may be achieved as the anomalously high jump of gains known from the discovery of volume ignition since 1978. This is considered for combination with the present most advanced experiments at the world highest class laser of NIF.

An anomalously strong increase of nuclear fusion gains for laser driven compression and thermal ignition of hydrogen-boron11 has been discovered from computations by using the latest results of Newins and Swain about details of a resonance maximum of the astrophysical S-function at 148 keV for the reaction cross-sections. Extensive computations based on volume ignition showed some usual improvements of the fusion gains. However, for a very narrow range of parameters, the increase of the gain was found to be higher by more than a factor 6. This is very unusual in all similar computations and is related to retrograde properties which were known for other parameter values. On top it is most important that the anomalous range is in the practically very interesting range for incorporation of laser pulse energies of few megajoules. The gains of up to 20 may be of interest for power generation in future by the high density fusion scheme.

Magnetic confinement fusion (MCF) based on neutral particle beam irradiation reached the highest gains with JET and is discussed in relation to the ITER project for a possible re-orientation with respect to the ignition process. Ignition plays a similar role for inertial confinement fusion (ICF). After a short review about specific ICF developments, the fast igniter development offered a re-consideration of igniting DT fuel at modest or low compression. The observation of extreme anomalies (Sauerbrey 1996, Zhang et al., 1998 and Badziak et al., 1999) at interaction of picosecond (ps) laser pulses above TW power could be explained as a skin layer mechanism based on earlier computations (Hora et al., 2002) with nonlinear (ponderomotive) force acceleration. The resulting very high ion current density space charge neutral plasma blocks interacting as pistons to ignite DT may lead to a new scheme of laser fusion with low cost energy generation.

Studies of single-event laser-target interaction for fusion reaction schemes leading to volume ignition are discussed. Conditions were explored where single-event ns-laser pulses give rise to temperatures sufficient for volume ignition. Thus, ignition is possible, particularly if X-ray reabsorption is sufficiently high. Unfortunately, this scheme requires laser pulses with energies above 5 MJ and target densities of compressed DT above 1000 g/cm−3. Both requirements are quite demanding for near term systems. Nevertheless the present state technology and the detailed knowledge about volume ignition at direct drive are a basis. Systems as NIF or LMJ can well confirm these physics-clarified conditions and the technology for large laser systems with sufficient repetition rate and for a drastic reduction of the size and costs is necessary and possible and by physics similar to the known reductions in transistor development.