An attempt is made to unite the concepts of atmospheric electricity and of lower ionospheric physics by using a common theoretical approach to derive profiles of electron and ion densities from 0 to 100 km. Relations between height and the rate of ion production that apply to average geographical and temporal conditions are used, together with selected values of attachment, detachment, and recombination coefficients. The uncertainty in and range of variation of these coefficients are discussed, and some examples given of the associated variability in the derived electron and ion density profiles. Estimates of collisional frequencies are used in conjunction with the electron and ion density information to obtain profiles of conductivity versus height. Below some 40 to 50 km, ionic conductivity is dominant. Deductions regarding mobility and its relationship to ion‐clustering are considered. It is demonstrated that when ionization is being produced below about 40 km, the radio wave absorption due to ions is much more important than that caused by electrons. It is also shown that any effects on atmospheric electricity observations at the ground associated with ionizing fluxes in the upper atmosphere are probably due to stratospheric space charges rather than to changes in conductivity at high altitudes. The applications of the conductivity profiles to radio wave propagation at VLF and ELF are briefly examined.

The resonan ces of th e earth ion os ph e re cav it y a re con s id e red d irectly as a ca vit y probl e m ra th er than as a limitin g case of propaga tion in a qua si-waveguid e with a n a rbitra ry (s ph e ri c a ll y sy mm e tri c) co ndu ctivity profil e. By u sing an approx im ation to a th c oreti ca ll y de rived prof ti e, va lu es fur the frequ encies and Q fac to rs of th e lowe r resona nces are computed whi c h compare with ex perim e ntal res ult s as we ll as or be tte r than th e valu es de ri ved fro m pre violl s mode ls. Th e e ffec ts of s ma ll c hanges in th e profil e are a lso co nsidered . It is s hu wn th at ioni c condu c li un in th e lower atmos phere s ho ul d not b e neglected a nd that th e " kn ee" in th e conductivity profil e wh e r e th e tra ns ilion from ioni c to e lectro ni c cond uc ti vit y occ urs has a s ig nifi ca nt , a nd p re vio us ly unrecog ni zed, effec t, parti cu la d y on th e Q fac to rs of th e res o na nt mod es.

It is shown that, if electrons of relativistic energies are generated within thunderstorms and then 'run away' upward above the thunderclouds, their range is probably only a few kilometers; their ionizing effects are therefore localized. Calculations indicate, however, that the bremsstrahlung produced during the stoppage of the electrons can create ionized columns extending to ionospheric heights (about 100 kin). If the original runaways exist the bremsstrahlung must be generated, and the possibilities for their detection experimentally are considered. There appears to be a sufficient flux of Compton-scattered photons for detection at thunderhead altitudes at a few kilometers from the thunderstorm.

No abstract

It is shown that information about the nuclear electromagnetic-transition vertex derived from experimental inelastic-scattering cross sections for electrons may be used to evaluate the nuclear-polarization (dispersion) corrections to the levels of muonic atoms. A modelindependent result is obtained for the contributions of discrete nuclear states. The most important systematic features of nuclear-excitation spectra, the giant-dipole resonance and the quasielastic peak, are considered in detail. The Goldhaber-Teller model is used for the former, and a simple-harmonic-oscillator shell model for the latter. Numerical estimates are obtained for total level shifts of low-lying muon states in nuclei with closed (harmonic-oscillator) proton shells, using closure approximation for the muon. The muon closure energies are considered in detail. It is felt that the results obtained are probably accurate to a factor of 2. The shifts are estimated to be several keV for the Is state in heavy nuclei, and somewhat less (a few tenths to about 1 keV) for the 2s and 2p states. These shifts are significant in comparison to the present accuracy of measurement of muonic x-ray spectra, and should be considered in calculations to fit nuclear-charge distributions . H*Y RQ (Sl q )(f\\M K (q)\\i) _ K + J.-MJ J f K J i J T (qL.= £(-) f f( J 1 KQ \-M Q M. J %