Helicity or Vortex Generation in Hydrodynamic (HD), Magneto-hydrodynamic (MHD), and effectrohydrodynamic (EHD) Regimes

摘要

Usually the source-origins of helicity or vortex generation have been considered to be thermohydrodynamic in the hydrodynamic (HD) regime and/or magnetohydrodynamic in the magnetohydrodynamic (MHD). Then fluid helicity is defined as hF=υ·Ω(υ:fluid velocity, Ω:fluid vorticity, like-wise magnetic helicity is defined as hM=υ· H (H: magnetic field). It has been shown, however, by the present author that an effectric quadrupole is also capable for helicity or vortex generation and a new effectric helicity defined as hE=υ·E (E: effectric field) has been introduced. Accordingly, we have now three kinds of helicity, namely fluid, magnetic, and effectric helicity. In many cases of atmospheric and space effectricity phenomena in nature, helicity or vortex generation is involved as typically seen in tornadic thunderstorms. Conventional theory of tornadic thunderstorms, however, space-charge and effectric fields have never been considered properly so far, surprisingly in spite of their effects of significance, because of no theorv for such cases, although those effects have been recognized implicitly by field experiments. This paper fills up these demands by newly introducing the concept of 'effectric Helicity' based on `effectrohydrodynamics (EHD) established and developed over the last more than two decades and such a whole theory is applied to tornadic thunderstorms.