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Home > Publication > Memoirs of the Kakioka Magnetic Observatory > Memoirs of the Kakioka Magnetic Observatory Vol.02 No.02,03 >On the Geo-electromagnetic Variations of Shorter Period

Memoirs of the Kakioka Magnetic Observatory Vol.02 No.02,03, p.82, March, 1940

On the Geo-electromagnetic Variations of Shorter Period

Hoshi, T.


 Assuming that the geo-electro-magnetic variations are produced by a known agency of external origin and that the earth is a homogeneous isotropic medium for the case of short periodic variations of the order less than somo few minutes,the components of the magnetic field and electric field under general consideration are given as follows:
  Br= − 1/rsinθ・∂/∂θ(sinθ・∂π2/∂θ) −1/rsin2θ・∂π2/∂α2
  μCr=−( 1/rsinθ・∂/∂θ(sinθ・∂/∂θ)+1/rsin2θ・∂2/∂α2)V2π2
  Bθ= 1/rsinθ・∂/∂α(V・2π2) +1/r・∂2(rπ2)/∂r∂θ
  μCθ=1/r ・∂2/ ∂r∂θ (V・2π2) - 1/sinθ・∂/∂α(V・2π2)
  Bα= −∂/∂θ(V・2π1) + 1/rsinθ・∂2(rπ2)/∂r∂α
  μCα=1/r sinθ・∂2/ ∂r∂α (rV・2π1) + ∂/∂θ(V・2π2)
  where B is magnetic induction , C is total current density composing of conduction current and displacement current and π1, π2 which may have the form πexp(-ipt), are any functions satisfying the condition
  V・2π+(4πρμ/c2・ip + εμ/c2・p2)=0
  In a particular case where radial component of the magnetic field is existent, the functional forms are
  π1=0, π2=1/(r)1/2 (AnJn+1/2(ξr))+BnJn+1/2(ξr))Pnt(cosθ)exp(-ila),
  where An,Bn are constants to be determined form boundary conditions and
  ξ=p(εμ)(1/2)((4πρ/εp)2+1)(1/4) exp(t・φ/2),φ=arctan(4πρ/εp)
  We have applied the above analysis to the variability of vertical component of geomagnetism and related phenomena of the earth-current, and come to the conclusion that the variability and E-W component of the earth-current must behave in a likely mood or the Phase-difference between them is 0 or π, and N-S component is π/2 behind the variability.
  Conference to the observational data supports that the analysis holds good, but observation made at Toyohara
  Magnetic Observatory contain some difficulties with the another is inclined to attribute to some local anomalies.

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