An investigation has been made to study the cosmic-ray decreases occurring during 2006 with respect to the arrival times of interplanetary shocks and magnetic clouds. We have identified three interplanetary magnetic cloud events during 5 February 2006, 13 April 2006 and 14 April 2006. The interplanetary magnetic field (B), north-south component of interplanetary magnetic field (Bz), solar wind velocity, sunspot number (R) and disturbance storm time index (Dst) associated with these events has been studied in the present work. Data (neutron monitor count rate) from Newark Neutron Monitor 9NM64 has been used. The north-south component of IMF (Bz) produce large geomagnetic disturbance on the onset of interplanetary magnetic clouds. The deviations in the interplanetary and solar wind plasma parameters are significantly correlated to the magnetic cloud events. The increase in Dst index, sunspot number (R) and Bz after the magnetic cloud event produces increase in cosmic ray intensity.
Table of Contents
Introduction
Interplanetary Magnetic clouds :
Nature of Magnetic clouds :
Size of the Magnetic clouds :
Type of Magnetic clouds :
Influence of magnetic clouds on comic ray intensity:
Magnetic clouds preceded by shock and cosmic ray intensity variations
Magnetic clouds followed by stream Interface and cosmic ray Intensity variations :
Magnetic cloud associated with cold magnetic enhancement and cosmic ray intensity variation :
Data and analysis
Velocity of solar wind :
Interplanetary magnetic field :
North South component (IMF, Bz) :
Disturbance Storm time (Dst) index :
Results and Discussion
Research Objectives and Core Topics
The primary research objective of this work is to systematically investigate the impact of interplanetary magnetic cloud events on cosmic ray intensity and associated geomagnetic and solar wind plasma parameters during the year 2006. By analyzing specific events in February and April 2006, the study seeks to determine the correlation between the onset of these magnetic disturbances and the resulting fluctuations in cosmic ray modulation.
- Analysis of cosmic ray intensity variations during interplanetary disturbance passages.
- Study of the relationship between interplanetary magnetic field (IMF) components and magnetic clouds.
- Evaluation of solar wind plasma parameters including velocity, density, and temperature.
- Assessment of the geomagnetic disturbance ring current via the Dst index.
- Investigation of Forbush-type decreases and their connection to interplanetary shocks.
Excerpt from the Book
Interplanetary Magnetic clouds :
Magnetic clouds belong to one of the several classes of transient flows in the solar wind. Magnetic clouds as ideal force free objects (cylinders or spheres) are ejected near the sun and followed beyond the Earths orbit. Magnetic clouds were discovered in 1970 by in situ space craft measurements as region in the solar wind where (1) the magnetic field magnitude is higher than the average: (2) the smooth magnetic field vector rotates through a large angle order of a day (3) proton temperature is lower than the average (Burlaga, 1988). All three of these criteria must be satisfied if an event is to be identified as a magnetic cloud.
A cylindrical magnetic cloud is introduces in the computational region through the inner boundary (at 18 solar radii) as a Lundquist force free solution (Burlaga, 1988). This cloud has its axis lying in the ecliptic plane. Another spherical magnetic cloud is also introduce in the same inner boundary (at 18 solar radii) as a Chandra Sekhar force free solution (Vandas et al., 1993 a).
Summary of Chapters
Introduction: This chapter defines magnetic clouds as transient solar wind phenomena, detailing their physical characteristics, historical discovery, and theoretical force-free structural models.
Data and analysis: This section describes the methodological approach, including the use of Newark Neutron Monitor data, trend correction methods, and the parameters used for evaluating solar wind velocity.
Interplanetary magnetic field : This chapter examines the origin and behavior of the interplanetary magnetic field (IMF), including the North-South component (Bz) and the role of the Disturbance Storm time (Dst) index in geomagnetic activity.
Results and Discussion: The final chapter presents the empirical findings regarding the February 5, 2006 magnetic cloud event, analyzing data plots to correlate cosmic ray intensity with solar wind and magnetic field parameters.
Keywords
Cosmic Ray Intensity, Magnetic Clouds, Interplanetary Magnetic Field, Solar Wind, Forbush Decrease, Geomagnetic Disturbance, Dst Index, IMF Bz, Solar Ejecta, Plasma Parameters, Space Physics, Coronal Mass Ejections, Neutron Monitor, Solar Dynamics, Magnetosphere
Frequently Asked Questions
What is the core focus of this research paper?
This paper focuses on the variations in cosmic ray intensity during the occurrence of interplanetary magnetic clouds, specifically examining data from the year 2006.
What are the central themes discussed in the text?
The central themes include the structure and dynamics of magnetic clouds, their interaction with solar wind, the resulting impact on cosmic ray flux, and the correlation with geomagnetic storms.
What is the primary objective of this investigation?
The goal is to study how interplanetary magnetic cloud events influence cosmic ray intensity and to assess how these clouds affect solar wind and geomagnetic parameters when they arrive at Earth.
Which scientific methodology is primarily applied?
The study uses empirical data analysis from the Newark Neutron Monitor, comparing cosmic ray count rates with interplanetary plasma parameters and employing the methodology established by Zhang and Burlaga.
What topics are covered in the main section of the paper?
The main sections cover the definition and classification of magnetic clouds, the behavior of IMF components, the Dst geomagnetic index, and a results analysis of specific 2006 events.
Which keywords best characterize the work?
The work is best characterized by terms such as Cosmic Ray Intensity, Magnetic Clouds, IMF Bz, Disturbance Storm time, and Solar Wind Plasma.
How is a magnetic cloud physically defined within this study?
It is defined by three criteria: higher-than-average magnetic field magnitude, a smooth rotation of the field vector over a day, and lower-than-average proton temperature.
How does the southward turning of the magnetic field (Bz) affect geomagnetic activity?
The text explains that the southward turning of the Bz component leads to efficient mass and energy transfer into the magnetosphere, resulting in significant geomagnetic disturbances reflectible in the Dst index.
What did the data comparison for the February 5, 2006 event reveal?
The analysis showed a significant correlation between the onset of the magnetic cloud, a subsequent decrease in the Dst index, and periodic increases followed by depressions in cosmic ray intensity.
- Citar trabajo
- Rajesh Kumar Mishra (Autor), Rekha Agarwal (Autor), 2024, Cosmic Ray Intensity Variation During the Passage of Interplanetary Disturbances, Múnich, GRIN Verlag, https://www.grin.com/document/1443130
