Equations describing the linear evolution of a non-dissipative Langmuir wave in inhomogeneous nonstationary anisotropic plasma without magnetic field are derived in the geometrical optics approximation. A continuity equation is obtained for the wave action density, and the conditions for the action conservation are formulated. In homogeneous plasma, the wave fieldẼ universally scales with the electron density N asẼ ∝ N 3/4 , whereas the wavevector evolution varies depending on the wave geometry.

A spinning ideal gas in a cylinder with a smooth surface is shown to have unusual properties. First, under compression parallel to the axis of rotation, the spinning gas exhibits reduced compressibility because energy can be stored in the rotation. Second, the spinning breaks the symmetry under which partial pressures of a mixture of gases simply add proportional to the constituent number densities. Thus, remarkably, in a mixture of spinning gases, an inverse problem can be formulated such that the gas constituents can be determined through external measurements only.

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Relativistic electrons can be accelerated by an ultraintense laser pulse in the "supra-bubble" regime, that is, in the blow-out regime ahead of the plasma bubble (as opposed to the conventional method, when particles remain inside the bubble). The acceleration is caused by the ponderomotive force of the pulse, via the so-called snow-plow mechanism. The maximum energy gain, ∆γ ∼ γga, is attained when the particle Lorentz factor γ is initially about γg/a, where γg is the pulse group speed Lorentz factor, and a is the laser parameter, proportional to the laser field amplitude. The scheme operates at a γg, yielding ∆γ of up to that via wakefield acceleration for the same plasma and laser parameters, ∆γ ∼ γ 2 g . The interaction length is shorter than that for the wakefield mechanism but grows with the particle energy, hindering acceleration in multiple stages.

A rotating plasma column is shown to exhibit unusual heat capacity effects under compression. For near equilibrium thermodynamics and smooth wall conditions, the heat capacity depends on the plasma density, on the speed of the rotation, and on the mass ratio. For a certain range of parameters, the storage of energy in the electric field produces a significant increase in the heat capacity.