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NOVEL MODEL OF ATMOSPHERIC ELECTRIC FIELDV. KuznetsovInstitute of Space Physical Researches, KAMCHATKA, [email protected] [email protected] http://www.ikir.kamchatka.ru/vvk/

- Novel model of atmospheric electric field (AEF) based on the idea of AEF generation due to electric charges separation in “fair weather” atmosphere is proposed.

- If thunderstorms are absent then the electric charges in the atmosphere are formed through its ionization by galactic cosmic rays (GCR).

- Light positive ions are lifted by upward currents to the upper layers of atmosphere and heavy negative aerosols fall to the Earth.

- The model provides the explanation for Carnegie curve of AEF and for some other features of atmospheric electricity; in particular, AEF behavior and Forbush decreases of GCR during geomagnetic disturbances.

- The problem of AEF secular decrease against the Earth surface temperature, the results of experiments on AEF excitation, AEF behavior during earthquakes and seismovibrators run are discussed.

- Motivation: the idea of AEF generation due to electric charges separation in “fair weather” atmosphere is proposed.
- ЕZ value which is almost constant for different Earth’s regions and in different seasons ЕZ= 130 V/m.
- Fine day electricity is associated with thunderstorm cloud activity, i.e. with the factor, which is excluded as an anomalous one in the investigations of “fair weather” field.

Atmospheric electric field model the idea of AEF generation due to electric charges separation in “fair weather” atmosphere is proposed. . Electric charges in the atmosphere..

The essence of our idea is that thunderstorms and strikes have impact on AEF, but they are not its main source.

According to the model charge formation (due to atmosphere ionization by GCR) and separation (due to the difference in charged aerosol falling rates) occur in “fair weather” atmosphere. In order to prove the case it is necessary, at first, to find convincing arguments that GCR can bring electric charge to the Earth, which is not less in value than the Earth looses per unit time I = dQ/dt = 103 coulomb/s.

Ion formation rate q is associated with cosmic ray flux density Р by the ratio: q = Р σ No, σ –effective cross-section of air ionization by cosmic rays, No – air molecule concentration.

Altitude distribution of electric charge density in the atmosphere (Marsh, Svensmark, 2000). As it is follows from the picture the air ionization in the part of the atmosphere, which is involved in AEF generationis due to GCR.

In the works ( atmosphere (Ermakov et al., 1997; Ermakov, Stozhkov, 2004) it was experimentally ascertained that atmospheric air ionization by cosmic rays q occurs according to the ion balance linear equation: q =β N but not to the usually applied quadratic equation q = αN2. Here α – volume recombination coefficient, β – linear recombination coefficient, these coefficients are different in value and dimension. The discovered dependence points that the relation between ion concentration in the atmosphere and cosmic ray flux is stronger (N ~ Р), than it was earlier supposed (N ~ Р1/2). This approach gives more confidence that GCR have significant impact on AEF and atmosphere conductivity current j. It is illustrated pictorially in Fig. where stable correlation between GCR flux N and j current (dQ/dt) is shown.

In the global scale there are three types of atmosphere ( particles size distribution in the troposphere: “background”, “oceanic” and “continental”. Idealized curves, exhibiting the features of these distributions are shown in Fig. (Ivlev, 1999).- The maximum aerosol concentration corresponds to the size r ≥ 0.1 mkm (from this point on we shall be interested in the particles particularly of this size).-Charged particles separation occurs on water droplets and heavy ions, that is why it is necessary to find out if there are appropriate conditions in the atmosphere for condensation and coagulation of the droplets with the radius r ≥ 0.1 mkm.

- Charged water aerosols and heavy ions fall to the Earth’s surface and transfer their charge to it. Aerosols evaporate when falling to the Earth. The critical size of particles for starting to evaporate was estimated in (Harrison, 2001).
- It was shown that the most optimal size of water aerosol is 0.13 mkm.
- As it is shown in Fig.,
- oversaturation value in
- the optimal case
- is Sc ≈ 1.006 (0.6%).

- Critical water vapor oversaturation dependence on temperature Sc(T) is illustrated in Fig., it was done by Artukhin A.S.
- The calculations were carried out according both to the classical theory (1) and to the quantum-statistical one (2).
- In the latter case the results of the calculations were almost similar to the experimental points, defined in the presence of supersonic air flow in cloud and diffusive chambers.
- Water aerosol formation region
- with the typical size
- r ≥ 0.1 mkm
- coincides with the region of
- maximum ion concentration
- generated by GCR stagnation.

Charge separation in gravitational field. temperature

- Frenkel evaluates ЕZ value inside a cloud using its water content М:
- ЕZ = εоMgζ/6πησe.
- where: M – cloud water content (М ≈ 1 g/m3 in a thunderstorm cloud), g – acceleration of gravity, ζ – water electric potential
(ζ ≈ 0.25 V), η – air viscosity (η ≈ 10-5 Pа s),

σe- electroconductivity (σ ≈ 10-14 Ω-1 m-1); ЕZ ≈ 104 V/m.

- Following Frenkel’s formula we estimate Еvalue appearing if charge separation takes place in “fair weather” water saturated atmosphere. Atmosphere water content (in the form of water aerosols) M for ЕZ = 100 V/mshould be a 100 times as little as in a cloud, i.e. М = 0.01 g/m3.. Realization of certain pT conditions is necessary for small aerosos to be generated in the atmosphere.

E polarity temperature . Condensation and evaporation processes effects.

- AEF model we consider, as well as Frenkel model, determines the Earth charge polarity by the fact that the droplets carrying a negative charge are heavier than the droplets carrying a positive charge.
- The physics of competition between condensation and evaporation processes in the atmosphere.
- Condensation rate К (s-1 cm-3)can be evaluated via vapor temperature:
- К exp (-2 + 1/T).
- In evaporation conditions (boiling) droplets collapse and vapor “bubbles” generate with the rate J (s-1 cm-3):
- J exp(-W/kT),here W – energy necessary for the generation of a bubble with a critical size. Temperature dependence of К and J is shown in the next Fig.

E polarity temperature . Condensation and evaporation processes effects.

- Temperature dependence (lg) of condensation (К) and evaporation (J) rates - the upper part.
- At the bottom is the polarity of electric field Е(z) as a function of the ratio J and К:Е + when J > Кand Е -, when J < К.
- E = 0, when T”≈ 24 ˚ C

Global distribution of atmospheric electric fields: electric field Е(z) & Earth temperature T.

Global distribution of atmospheric electric fields: electric field Еz & Earth temperature T.

- In the last 80 years Еz-value has decreased by half: Еz’ ≈ 2.
- The Earth surface temperature has increased by 0.7 – 0.8 ˚:T’ = 0.06, namely: T’/E’ = 0.03.
- Water concentration of the Earth atmosphere depends on the nucleation rate:
- M ~ nZ (4πrPK)/(2π m kT)1/2, here n - water concentration, r – radius, m - mass, Z – Zeldovitch factor, Р – pressure,
- К exp (-T), k – Boltzmann constant. Since ЕZ depends solely upon temperature, we obtain:
ЕZ M T-1/2 exp (-T).

- If Т = аt, then Т’ = dT/dt = а. SubstitutingТ = аt into the formula for Еz’ we have
Еz’ ≈ [exp(-at)(1 + 2at)/а] ×(at)3/2

and assuming t =1 we obtain the relation T’/E’ ≈ 2а3/2. Revealed in measurements a equal to а = 0.06 ensures

T’/E’ = 0.03.

AEF Universal diurnal variation. field Carnegie curve.

- a – Cosmic ray intensity distribution, obtained by UoSAT spacecraft from 09.1988 to 05.1992 (Glassmeier et al., 2002) in the northern hemisphere (the North is in the bottom);
- b –isoline of geomagnetic field H-component value 10 μT (marked by black area, the North is in the bottom);
- c –Atmospheric electric field ЕZ UT-variation.
- Carnegie curveAEF is accounted for assymmetry of the geomagnetic field structure.

AEF Universal diurnal variation. field Model.

- Averaged atmospheric electric field value (relative units) at Vostok, Antarctica, measured during 1998 (Corney, et al., 2003).
- Earth’s orientation is as regards to GCR flux direction (arrows) at equinox,in winter and in summer.
- Angles and “funnels”
- correspondto GMA [2]:
- the Canadian GMA is
- located
- at the latitude
- φ1 ≈ 55° N,
- the Siberian GMA is at
- φ2 ≈ 63° N.

Universal variation in the ionosphere. field

foF2 universal variation averaged for the years of minima (а), maxima (b) for three cycles of solar activity depending on season (c) (Kuznetsov et al., 1998).

Universal variation in the ionosphere. field

- Magnetic field line structure in the
- region of Northern Magnetic Pole
- (NMP) and Global Magnetic
- Anomalies: the Canadian Anomaly
- (CA) and the Siberian Anomaly (SA).

- Correlation of Forbush decreases in GCR with field EZones observed – a;
- b – GCR spectrum pointing at the number N of particles with energy E: 1 – region of low energy GCR, 2 – that of middle energy GCR, 3 - that of higher energy GCR.
- Altitude distribution of GCR density n (r.u.) of GCR providing the EZgeneration distributed along the altitude h (km).

NOVEL MODEL OF ATMOSPHERIC field ELECTRIC FIELG

- MAIN PRINCIPLES OF AEF MODEL:
- 1. ATMOSPHERE IONIZATION BY GCR.
- 2. CHARGES SEPARATION BY THE FINE AEROSOLS OF ATMOSPHERE IN FAIR- WEATHER CONDITIONS.
- 3. TIME STABILITY OF ATMOSPHERIC ELECTRIC FIELD PROVIDED BY CONSTANCY OF THE EARTH TEMPERATURE AND OF THE RATES OF PHASE CHANGES IN WATER.
- 4. MODEL OF THE UNITARY VARIATION (Carnegie curve) FOLLOWING FROM ASSYMETRY OF THE GEOMAGNETIC FIELD.

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