Please use this identifier to cite or link to this item: http://hdl.handle.net/10603/66112
Title: A study on the radiopulses from extensive air showers at metre wavelengths
Researcher: Barthakur, Sunil Kumar
Guide(s): Pathak, K M
Keywords: Asymmetry
Atmospheric
Cerenkov
Cosmic
Emission
Radiopulses
Wavelengths
University: Gauhati University
Completed Date: 30/11/1978
Abstract: Radiopulses from extensive air showers (EAS) at 44, 60 and 80 MHz frequencies have been studied at the Cosmic Radiation Research Laboratory, Department of Physics, Gauhati University, India during 1971-78. The experimental arrangement set up for the investigation, consisted of (i) a Geiger- Mueller counter array and the associated circuits for the detection of near zenith EAS (gt/ 1016 eV), (ii) two sets of broad-side antenna systems for detection of radiopulses at 44 and 60 MHz frequencies and one set of stacked yagi arrays for 80 MHz frequency, and (iii) an automatic recording device that recorded the events displayed in the CRO. Data were collected for about 1150 hours, during the autumn and the winter seasons from 1972 to 1978, and altoge- ther 2729 showers were recorded. The emission of detectable radiopulses from EAS gt/ 1016 eV at different frequencies is confirmed. The experi- mental results support the theoretical prediction that the field strength of radioemission depends on the shower size and hence on the energy of the primary. An asymmetry has been noticed in the field-strength distribution of the radiopulses detected by the North-South (N-S) and the East-West (E-W) directed arrays. These obser- vations are in good agreement with the theory that charge separation mechanism is predominant in generating radiopulses from EAS, and that the radioemission is polarised in the E-W direction. The frequency spectra of the radiopulses at 44, 60 and 80 MHz frequencies are found to decrease in each case, with frequency. Further, the observation of radioemission at 80 MHz indicates the invalidity of the limit of radioemission above ~ 75 MHz frequency as was predicted by Askaryan (1962) according to his charge excess mechanism. The correlation between simultaneously produced radio-pulses from EAS at 60 and 80 MHz frequencies is studied for the first time in details. The statistical analyses indicate highly significant positive correlation between the radio-pulses at these two frequencies. It is concluded that the...
Pagination: 
URI: http://hdl.handle.net/10603/66112
Appears in Departments:Department of Physics

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01_title page.pdfAttached File14.76 kBAdobe PDFView/Open
02_certificate.pdf23.9 kBAdobe PDFView/Open
03_abstract.pdf49.52 kBAdobe PDFView/Open
04_preface.pdf42.88 kBAdobe PDFView/Open
05_content.pdf94.63 kBAdobe PDFView/Open
06_chapter 1.pdf329.32 kBAdobe PDFView/Open
07_chapter 2.pdf1.33 MBAdobe PDFView/Open
08_chapter 3.pdf2.25 MBAdobe PDFView/Open
09_chapter 4.pdf453.51 kBAdobe PDFView/Open
10_chapter 5.pdf329.07 kBAdobe PDFView/Open
11_discussion and conclusions.pdf386.96 kBAdobe PDFView/Open
12_appendix i.pdf35.05 kBAdobe PDFView/Open
13_appendix ii.pdf453.71 kBAdobe PDFView/Open
14_appendix iii.pdf14.42 kBAdobe PDFView/Open
15_bibliography.pdf237.48 kBAdobe PDFView/Open
16_list of publications of the author.pdf29.6 kBAdobe PDFView/Open
17_acknowledgement.pdf61.5 kBAdobe PDFView/Open


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