plasmaphysics

It is only a slight run just to polish my mind
To avoid the enormous, insurmountable difficulties coming from the plasma instabilities occurring in the normal Tokamak systems nearing to that temperature and pressure necessary to the ignition of the fusion (Lawson criteria), an idea occurred to me: is it possible to combine the advantages of the inertial fusion solution and the Tokamak system in a hybrid Tokamak arrangement? According to my idea I find promising to ignite the fusion of the deuterium " tritium fuel mixture in the Tokamak torus only in a short (10-30mm), narrowed section of the vacuum-tube of the Tokamak system, that is, in a given cross section of the Tokamak torus, using the successful results of the inertial fusion arrangements. Here one could use also soft X-ray beams, but cylindrically ( symmetrically) concentrated onto the previously preheated, magnetically confined D-T plasma thread on that short section of the torus to compress it until the Lawson criteria is satisfied, and the fusion ignited without any ablation also.
In the Inertial Fusion Devices the frozen deuterium-tritium pellet-target has been ignited by radiating it with soft X-ray beams concentrated spherically onto a small ball shaped pellet. It is true there the ablation of the frozen fuel shell contributes to the ignition in a great extent.

The plasma fuel is driven into that fusion section of the vacuum tube by the well known driving methods of the Tokamak equipments, and once the fusion has been started the fuel can be hold there until the necessary length of time. The feeding of the fresh fuel mixture would be driven periodically within the torus, with the rate the burning of the fuel has been occurred. This was that idea which grasped me, because it could be controlled by the help of the present technologies.

The D-T plasma is preheated and compressed in the vacuum tube of the Tokamak by the well " tried methods until the limits of stability, that is the fuel reach an energy of cca. 5-6 keV, which is today well controllable, the missing energy necessary for the ignition of the fuel could be transferred from the cylindrically concentrated soft X-ray beam. The radiation can be obtained from a high power laser source (100kW-1MW, like the Nova and Vulcan systems ), the laser beam is converted into soft X-ray radiation with a relatively high efficiency ( approx. 80% efficiency as I learned). The effectiveness of the system can be significantly enhanced by applying a hohlraum around the fusion section, the soft X-ray radiation is concentrated not directly onto the plasma thread, but on the surrounding hohlraum, by the help of which the transferred energy necessary for the ignition of the fusion can be lowered in a great extent, - as calculated in the case of the inertial fusion system - from 30 keV to as low as a few keV. By the help of this hohlraum the symmetry of the radiation is automatically assured.
Of course the exact value is a question of experiments.
In the case of the pellet ignition the Lawson criteria was satisfied at a lower level of temperature and pressure, because of the inertia of the compressed fuel material and because of the ablation of the pellet-shell as I mentioned.
In the hybrid Tokamak the compressed plasma thread has its own inertia as well, keeping back the fuel nucleus escaping from the fusion cross section during the irradiation process, and the surrounding magnetic confinement has also a retaining effect, but we can not calculate with the ablation of the pellet shell, but I hope, other advantages of this hybrid arrangement could compensate this drawback.

This inertia of the compressed fuel should exist also because the soft X-ray radiation is pulsed with a high frequency due to the pumped energy transfer of the laser beam and because the particles cannot leave the fusion cross section at the two ends of the plasma thread where the cross section of the plasma-ends are 3-4 order of magnitudes less than the length of the plasma thread and also because of the retaining force of the magnetic confinement.

The alpha particles and the neutrons developed as a result of the fusion procedure can contribute to the further heating the plasma thread on the ignition section, decreasing also the need of the transferred ignition energy, thus minimizing the damaging effect of the neutron radiation on the structural element of the mechanical system. All other means i.e. the appropriate divertors, developed for the converting and transferring the energy generated during the fusion process, and the procedures to remove the superfluous alfa particles is applicable. If the hybrid Tokamak works, one could apply more effective methods extracting the energy gain.
Is it a hopeless way ? Help me please