Penetration of thundercloud electric fields into the ionosphere and magnetosphere: 1. Middle and subauroral latitudes

Abstract

The mapping of thundercloud electric fields at middle and subauroral latitudes is investigated analytically as a three‐dimensional boundary value problem. The electrical conductivity is represented by several piecewise exponential functions of altitude, and the anisotropy of the medium is taken into account above 70‐km altitude. The geomagnetic field lines are assumed to be straight and vertical below 150‐km altitude. Electric field strength at great heights depends sensitively on conductivity and thundercloud models used in the calculations. Sample calculations using representative nighttime profiles show that ‘giant’ thunderclouds can produce transverse electric fields of tens of microvolts per meter in the equatorial plane of the midlatitude magnetosphere. In the daytime, corresponding electric fields are about an order of magnitude less. These results suggest that giant thunderclouds may be an important source of localized electric fields that can form field‐aligned electron density irregularities in the ionosphere and the magnetosphere.

Decrease of the electric field penetration into the ionosphere due to low conductivity at the near ground atmospheric layer

“…In this connection it is essential to understand how electric fields from lithospheric origin penetrate into higher altitudes of the atmosphere. The first theoretical investigations of the penetration of an electrostatic field from the lithosphere into the ionosphere were done by Park and Dejnakarintra (1973). These authors analytically studied the penetration of thundercloud electric fields into the ionosphere and the magnetosphere.…”

Ionospheric conductivity effects on electrostatic field penetration into the ionosphere

“…In this connection it is essential to understand how electrostatic fields from lithospheric origin penetrate into higher altitudes of the atmosphere. Theoretical investigations are generally based on the work of Park and Dejnakarintra (1973). This approach was mainly applied to study the penetration of thundercloud electric field into the ionosphere and the magnetosphere.…”

“…The conductivity of the atmosphere is found to be a key physical parameters in the processes which occurred between the ground and the other layers, in particular the ionosphere (James, 1985;Kim and Khegay, 1985;Kamra and Ravichandran, 1993). A second application of the model of Park and Dejnakarintra (1973) is discussed and investigated in the frame of the studies of the seismic precursor emissions. In this case the electric field of seismic origin is analyzed in the way to estimate the effect of such field within the ionosphere (Gokhberg et al, 1984;Kim et al, 1994;Pulinets et al, 1998).…”

Lightning-generated whistler waves observed by probes on the Communication/Navigation Outage Forecast System satellite at low latitudes

“…Kelley et al [1985] carried out the first rocket-borne ionospheric measurements of vector electric fields over thunderstorms and demonstrated that the lightning pulse amplitude was 2 orders of magnitude larger than those of middle latitude ambient ionospheric electric fields, and as many as 3 orders of magnitude larger compared to the magnitude predicted in the scientific literature [cf. Park and Dejnakarintra, 1973]. Subsequent in situ measurements in the upper atmosphere and ionosphere [Holzworth et al, , 1999Kelley et al, 1990Kelley et al, , 1997Li et al, 1991] have clearly established that the lightning EMP (electromagnetic pulse) results in a strong, upward propagating energy packet that converts to whistler mode plasma waves in the ionosphere.…”