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Cosmic rays transport equation solution and wavelets analysis:A case of pulsar source

机译：宇宙射线传输方程解和小波分析：以脉冲星源为例

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摘要

Our purpose is to analyse time dependence of the cosmic ray particles density as a function of a modelled pulsar source variability using Morlet wavelets. Unlike the conventional spectral analysis the wavelet transform is a suitable tool for description of non-stationary processes containing multiscale features detection of singularities and analysis of transient phenomena. Methods such as wavelet should be very suitable; thus it can be applied to the problem under consideration. We have proceeded for the Morlet reconstructions to detect and predict new period details or singularities hidden behind the original spectra describing galactic cosmic ray density modulations as a response to a certain source. Wavelet coefficients calculated by the wavelet transform represent changes in the time series at a particular resolution. Thus it should be possible to filter out noise by looking at the time series in various resolutions. We present in this work semi-analytical solutions of cosmic rays transport equation for two cases of sources: time dependant discrete source and a pulsar source. When studying the case with time dependant source, a maximum for the Morlet decomposition coefficients was detected for a period of 4-5 years around the time of injection. For the same period the CR particles density presents a maximum and describes the two phenomena corresponding to creation and losses of particles. The observed characteristics of pulsars and the manner with which they would affect cosmic rays as sources of this radiation have been considered. We chose RP J0737-3039 A pulsar as a model of source. We used the Morlet wavelets to describe the oscillations of pulsar source to analyse the CR particles density. The description of the pulsar modelled source with a single Morlet wavelet shows characteristic periods of 23 ms, 2-5,8, and 20 s for different scale parameter values. The analysis of CR density as a response to this source reveals periods of 20, 8, 220-250 s. A more realistic description is given, modelling the source oscillations by a sum of Morlet wavelets. The CR density response to this source has mainly changed in paces showing more realistic behaviour. Informations contained in Morlet decompositions and reconstructions show essentially periods of 250, 300 and 25 s. This analysis of cosmic rays particle density and propagation through the Morlet wavelets provides us a detailed zoom of hidden periods and structures for CR particles density and generally variations versus time and energy in vicinity and far from the CR sources.
机译：我们的目的是使用Morlet小波分析宇宙射线粒子密度随时间变化的模型脉冲星源变异性函数。与传统的频谱分析不同，小波变换是描述非平稳过程的合适工具，该过程包含奇异点的多尺度特征检测和瞬态现象分析。小波等方法应该非常适合；因此可以将其应用于正在考虑的问题。我们已经进行了Morlet重建，以检测和预测隐藏在原始光谱背后的新周期细节或奇异点，而原始光谱将银河宇宙射线密度调制描述为对某个光源的响应。通过小波变换计算的小波系数表示特定分辨率下时间序列的变化。因此，应该有可能通过查看各种分辨率的时间序列来滤除噪声。我们在这项工作中介绍了两种情况下的宇宙射线传输方程的半解析解：时间相关离散源和脉冲星源。当研究时间依赖源的情况时，在注入时间附近的4-5年内检测到Morlet分解系数的最大值。在同一时期，CR颗粒密度呈现最大值，并描述了与颗粒产生和损失相对应的两种现象。已经考虑了脉冲星的观测特性以及它们作为辐射源影响宇宙射线的方式。我们选择RP J0737-3039脉冲星作为源模型。我们使用Morlet小波来描述脉冲星源的振荡，以分析CR粒子的密度。对具有单个Morlet小波的脉冲星建模源的描述显示了针对不同比例参数值的23 ms，2-5、8和20 s的特征周期。作为对此来源的响应，对CR密度的分析显示出20、8、220-250 s的周期。给出了更现实的描述，通过Morlet小波的总和对源振荡进行建模。对这种来源的CR浓度响应主要改变了步伐，显示出更现实的行为。 Morlet分解和重建中包含的信息基本上显示了250、300和25 s的周期。这种对宇宙射线粒子密度和通过Morlet小波传播的分析为我们提供了CR粒子密度的隐藏周期和结构的详细缩放，以及在CR源附近和远离CR源的情况下通常随时间和能量的变化。

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  • 来源
    《Acta astronautica》 |2011年第12期|p.1650-1659|共10页
  • 作者

    Ne ïla Zarrouk; Raouf Bennaceur;

  • 作者单位

    Laboratoire de Physique de la Matière Condensée, Faculté des Sciences de Tunis, Université Tunis El Manar, Tunisia;

    Laboratoire de Physique de la Matière Condensée, Faculté des Sciences de Tunis, Université Tunis El Manar, Tunisia;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    cosmic rays; transport equation; pulsar; wavelets;

    机译：宇宙射线传输方程脉冲星小波;

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