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| Eriksson's model | |||
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This model is not like earlier models in which the strike distance is function of current amplitude. This model considers height of object because we can assume that lightnings will be more attracted by them and that would match the real situation. It is made with more complex assumings and the main diference with the classic models is that we took in consider increasing of electric field near the high objects. Lightning can stike into the high object only when the top of leader reaches volume above structure which is determined with radius of attraction Ra. This model gives informations by regresion: (in every formula distances are in meters, currents in kiloampers, and the koeficients do not have their measures)
where is: Radius of attraction Ra is a distance for which all lightning strikes in the distance smaller than Ra are attracted by object. Radius of earths attraction is zero and only objects above ground have radius of attraction. Combining experimental and physical results Eriksson sugessted two formulas for that radius, one for pylons (Rat) and the other for horizontal electric lines (Rac).
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