# The International Cosmic Ray Conference 2017

12-20 July 2017
BEXCO
Asia/Seoul timezone
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# Contribution

BEXCO - Room F(201/202/203/204)

# [SH142] Deviation from normal diffusion of cosmic rays in different phases of Forbush decrease

## Speakers

• Anna WAWRZYNCZAK-SZABAN

## Description

Based on the galactic cosmic ray intensity (GCR) data from neutron monitors (NMs), solar wind velocity (SWV) and interplanetary magnetic field (IMF) components we study dynamical changes of stochastic conditions near to earth orbit during the Forbush decrease (Fd) of galactic cosmic ray intensity in November 2004. A whole course of the Fd is divided into five subintervals consisting of 1) an interval before the Fd, 2) decreasing phase, 3) minimum of the Fd, 4) ascending phase and 5) a final interval including of the cosmic ray intensity recovery period. To describe stochastically physical state of space where Fd was developing we use an index herein called as a ‘Brownian length’ L calculated as follows: for any point (hour) of time series $x_{j}$ (j=1,2, ldots, n) starting from $j =1$ we calculate a new series $L_{1}={ sqrt{(x_{2}-x_{1})^{2}}, sqrt{(x_{3}-x_{2})^{2}}, sqrt{(x_{4}-x_{3})^{2} } ,ldots, sqrt{( x_{n}-x_{n-1} )^{2}} }$ with resolution time $D_{t1} = t_{k}-t_{k-1}=1 hour$. Then we find an average of each series $L_{ik}={sqrt{(x_{i}-x_{i-k})^{2}}}$, where $k=1,ldots, n-1; i=1,ldots, n$ for $D_{tk} = t_{i}-t_{i-k}= 2,3, ldots, n-k$ hours. Similar calculations we perform for all parameters: GCR intensity, SWV, and IMF components. We determine the power type approximation $L_{ik} propto {D_{tk}}^{sigma}$. For GCR intensity the exponent changes in the range \$0.2