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Linear and Nonlinear Landau Damping With Non-Maxwellian Distribution Function

Thesis Info

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Author

Sehar, Sumbul

Program

PhD

Institute

Government College University

City

Lahore

Province

Punjab

Country

Pakistan

Thesis Completing Year

2019

Thesis Completion Status

Completed

Subject

Physics

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/10382/1/Sumbul%20Sehar_PhD_Physics.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676726585050

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In many physical situations where a laser or electron beam passes through dense plasma, hot low-density electron populations can be generated, resulting in a particle distribution function consisting of a dense cold population and a small hot population. Presence of such low-density electron distributions can alter the wave damping rate. Kinetic model is employed to study the Landau damping of Langmuir waves when a small hot electron population is present in the dense cold electron population with non-Maxwellian distribution functions. Departure of plasma from Maxwellian distributions significantly alters the damping rates as compared to the Maxwellian plasma. Strong damping is found for highly non-Maxwellian distributions as well as plasmas with higher dense and hot electron population. Existence of weak damping is also established when the distribution contains broadened flat tops at the low energies or tends to be Maxwellian. These results may be applied in both experimental and space physics regimes. Using non-Maxwellian generalized (??, ??) distribution function electron acoustic instability has been investigated in magnetized and unmagnetized four component plasma. We analyzed electron velocity distribution function using Cluster data when Cluster was traversing from the dayside mid-latitude cusp to plasma sheet boundary region in the southern hemisphere. Observed distribution is fitted with the generalized (??, ??) distribution, and the values of spectral indices for cold, hot and beam electron components obtained from fitting are used in the numerical results. We then investigated the effects of beam density, beam temperature, beam velocity and propagation angle on the real frequency and growth rate of the EAW for both magnetized and unmagnetized cases. These results are compared with Maxwellian results and found that using observed distribution and plasma parameters, real frequency and growth rate remain higher than the Maxwellian or kappa values exhibit significantly different behavior from the ideal conditions. Nonlinear Landau damping of Langmuir waves in two electron component plasma is studied. The numerical results show a significant difference between the Maxwellian and non-Maxwellian instantaneous damping rates when generalized (??, ??) distribution function is used. Normalized amplitude of the nonlinear damping rate for the generalized (??, ??) distribution function and also for Maxwellian distribution remain high when the distribution contains two electron populations as compared to one electron population. It is found that maximum instantaneous amplitude for generalized (??, ??) distribution function is higher than the Maxwellian instantaneous amplitude.
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مولانا مفتی عتیق الرحمن

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ان کے اس مرض کی المناکی دارالمصنفین سے بھی بڑی حد تک وابستہ ہے، اس لئے اس ادارہ کے خدام ان کی وفات حسرت آیات سے بہت سوگوار ہیں، فروری ۱۹۸۲؁ء میں یہاں ’’اسلام اور مستشرقین‘‘ پر جو سیمینار ہوا تھا، اس میں وہ شرکت کے لئے تشریف لائے تھے، تین روز یہاں بہت ہنسی خوشی سے گذارے، اس کے ایک اجلاس کی صدارت بھی کی، خوش خوش یہاں سے اور شرکاء کے ساتھ روانہ ہوئے تو ریل ہی میں بارہ بنکی کے پاس ان پر فالج کا سخت حملہ ہوا، ان کے ہم سفر مولانا سعید احمد اکبر آبادی اور مولانا سجاد حسین نے ان کو کسی طرح لکھنؤ کے ہسپتال میں داخل کیا، ان کی طبیعت کچھ سنبھلی تو پھر دہلی لے جائے گئے، اس وقت سے اپنی وفات تک تقریباً سوا دو سال تک بستر ہی پر رہے، خیال ہوتا ہے کہ وہ دارالمصنفین کا سفر نہ کرتے تو اس موذی مرض میں مبتلا نہ ہوتے، مگر مشیتِ ایزدی یہی تھی، راقم ان کی عیادت کے لئے کئی بار ان کی خدمت میں حاضر ہوا ان کا جسم تو بیکار ہوچکا تھا، مگر دماغ بیدار رہا، گفتگو میں وہی روانی اور شیر ینی ہوتی جو ان کی طبیعت کا مخصوص رنگ تھا، ہر قسم کے مسائل پر گفتگو کرتے، مگر زیادہ تر دارالعلوم دیوبند کے قضیۂ نامرضیہ پر اظہار خیال کرتے، ایسا معلوم ہوتا کہ وہاں کا المیہ پیش نہ آتا تو اس مرض میں مبتلا نہ ہوتے اور ہوتے بھی تو اتنے دنوں تک بستر علالت پر پڑے نہ رہتے، دارالعلوم دیوبند...

Analysis of Quarantine Service Quality on Ship Crew Satisfaction during the Covid-19 Pandemic at Belawan Sea Port

This study aims to analyze the quality of quarantine services on ship crew satisfaction during the Covid-19 pandemic at the Belawan Sea port. This study is a quantitative study with a cross sectional method which aims to analyze the quality of quarantine services on satisfaction during the COVID-19 pandemic at the Belawan Sea Port using the ServQual approach which consists of physical evidence, reliability, responsiveness, assurance, and empathy. The results of the study are expected to provide input regarding the quality of quarantine services provided by the Class I Medan KKP to ship crews during the COVID-19 pandemic. Based on the ServQual analysis, the results show that the satisfaction of the crew of the quarantine service at Belawan Port is very satisfying with a suitability level of 107.56% (the average service / reality score is 4.00 and the expectation score is 3.72). It is suggested to improve coordination and more intensive advocacy with shipping agents as intermediaries between officers and skippers as crew so as to reduce the length of service waiting time, in order to increase the number of human resources carrying out document checks on board, involving female medical officers for health checks The crew who came from affected countries/ports to facilitate information retrieval, ordered the boarding officers to bring Personal Protective Equipment when interacting with the crew.

A Comparative Study of Cognitive Learning Styles and Attitudes Among Science Students at Undergraduate Level

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