Owing to the focusing effect in the IMF mentioned, Mo and AM have values equal to 1 and 0.01, respectively (see numerical estimations by Fedorov and Stehlik, 1997).
2.29.3. Pitch-angle response function for neutron monitors
Fedorov et al. (2002) used the pitch-angle response function for neutron monitors y(X) which is similar to <p(y) in which p has to be replaced by X (X is the pitch-angle of an asymptotic NM direction related to the regular IMF direction). The value of Ao corresponds to the angle of a maximal sensitivity of detector, the parameter A^ characterizes a width of directional diagram of the neutron monitors.
According to Fedorov et al. (2002), an intensity enhancement of the registered by neutron monitors solar energetic particles arises suddenly at t = y for a ¿-like particle injection, and a width of the impulse peak connected with arriving of the first particles is very short. Usually one needs to suppose, based on the description of measured temporal profiles of past solar proton events, that the injection of high energy particles into the interplanetary medium has a finite duration, which is caused mainly by the propagation of accelerated particles in the solar corona (Lumme et al., 1986; Borovkov et al., 1987).
The injection of accelerated particles from the source into the IMF during a finite time can be represented by the following time injection function:
where the dimensionless quantity v-1 is an unique parameter, which characterizes the mean duration of the injection as well as the instant of maximum at Tm = v-1. It was assumed that t is measured in the dimensionless quantity t = tvs = vt/A , where A is the particle mean path. It is also reasonable to suppose that the duration of the emission by that 'particle source' of the lower energy particles is longer, so the quantity v0 will be dependent on the particle rigidity. Building all these 'weight' functions above into the consideration, a detector will register
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