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Heather Ratcliffe - One of the best experts on this subject based on the ideXlab platform.

  • large scale simulations of solar type iii radio bursts flux density drift rate duration and bandwidth
    Astronomy and Astrophysics, 2014
    Co-Authors: Heather Ratcliffe, Eduard P Kontar, Hamish A S Reid
    Abstract:

    Non-thermal electrons accelerated in the solar corona can produce intense coherent radio emission, known as solar type III radio bursts. This intense radio emission is often observed from hundreds of MHz in the corona down to the tens of kHz range in interplanetary space. It involves a chain of physical processes from the generation of Langmuir Waves to Non-Linear processes of Wave-Wave interaction. We develop a self-consistent model to calculate radio emission from a non-thermal electron population over a large frequency range, including the effects of electron transport, Langmuir Wave-electron interaction, the evolution of Langmuir Waves due to Non-Linear Wave-Wave interactions, Langmuir Wave conversion into electromagnetic emission, and finally escape of the electromagnetic Waves. For the first time we simulate escaping radio emission over a broad frequency range from 500 MHz down to a few MHz and infer key properties of the radio emission observed: the onset (starting) frequency, identification as fundamental or harmonic emission, peak flux density, instantaneous frequency bandwidth, and timescales for rise and decay. By comparing these large-scale simulations with the observations, we can identify the processes governing the major type III solar radio burst characteristics.

  • large scale simulations of solar type iii radio bursts flux density drift rate duration and bandwidth
    arXiv: Solar and Stellar Astrophysics, 2014
    Co-Authors: Heather Ratcliffe, Eduard P Kontar, Hamish A S Reid
    Abstract:

    Non-thermal electrons accelerated in the solar corona can produce intense coherent radio emission, known as solar type III radio bursts. This intense radio emission is often observed from hundreds of MHz in the corona down to the tens of kHz range in interplanetary space. It involves a chain of physical processes from the generation of Langmuir Waves to nonlinear processes of Wave-Wave interaction. We develop a self-consistent model to calculate radio emission from a non-thermal electron population over large frequency range, including the effects of electron transport, Langmuir Wave-electron interaction, the evolution of Langmuir Waves due to Non-Linear Wave-Wave interactions, Langmuir Wave conversion into electromagnetic emission, and finally escape of the electromagnetic Waves. For the first time we simulate escaping radio emission over a broad frequency range from 500~MHz down to a few MHz and infer key properties of the radio emission observed: the onset (starting) frequency, {identification as fundamental or harmonic emission}, peak flux density, instantaneous frequency bandwidth, and timescales for rise and decay. Comparing with the observations, these large scale simulations enable us to identify the processes governing the key type III solar radio burst characteristics.

Hamish A S Reid - One of the best experts on this subject based on the ideXlab platform.

  • large scale simulations of solar type iii radio bursts flux density drift rate duration and bandwidth
    Astronomy and Astrophysics, 2014
    Co-Authors: Heather Ratcliffe, Eduard P Kontar, Hamish A S Reid
    Abstract:

    Non-thermal electrons accelerated in the solar corona can produce intense coherent radio emission, known as solar type III radio bursts. This intense radio emission is often observed from hundreds of MHz in the corona down to the tens of kHz range in interplanetary space. It involves a chain of physical processes from the generation of Langmuir Waves to Non-Linear processes of Wave-Wave interaction. We develop a self-consistent model to calculate radio emission from a non-thermal electron population over a large frequency range, including the effects of electron transport, Langmuir Wave-electron interaction, the evolution of Langmuir Waves due to Non-Linear Wave-Wave interactions, Langmuir Wave conversion into electromagnetic emission, and finally escape of the electromagnetic Waves. For the first time we simulate escaping radio emission over a broad frequency range from 500 MHz down to a few MHz and infer key properties of the radio emission observed: the onset (starting) frequency, identification as fundamental or harmonic emission, peak flux density, instantaneous frequency bandwidth, and timescales for rise and decay. By comparing these large-scale simulations with the observations, we can identify the processes governing the major type III solar radio burst characteristics.

  • large scale simulations of solar type iii radio bursts flux density drift rate duration and bandwidth
    arXiv: Solar and Stellar Astrophysics, 2014
    Co-Authors: Heather Ratcliffe, Eduard P Kontar, Hamish A S Reid
    Abstract:

    Non-thermal electrons accelerated in the solar corona can produce intense coherent radio emission, known as solar type III radio bursts. This intense radio emission is often observed from hundreds of MHz in the corona down to the tens of kHz range in interplanetary space. It involves a chain of physical processes from the generation of Langmuir Waves to nonlinear processes of Wave-Wave interaction. We develop a self-consistent model to calculate radio emission from a non-thermal electron population over large frequency range, including the effects of electron transport, Langmuir Wave-electron interaction, the evolution of Langmuir Waves due to Non-Linear Wave-Wave interactions, Langmuir Wave conversion into electromagnetic emission, and finally escape of the electromagnetic Waves. For the first time we simulate escaping radio emission over a broad frequency range from 500~MHz down to a few MHz and infer key properties of the radio emission observed: the onset (starting) frequency, {identification as fundamental or harmonic emission}, peak flux density, instantaneous frequency bandwidth, and timescales for rise and decay. Comparing with the observations, these large scale simulations enable us to identify the processes governing the key type III solar radio burst characteristics.

Anatoly Zlotnik - One of the best experts on this subject based on the ideXlab platform.

  • an explicit staggered grid method for numerical simulation of large scale natural gas pipeline networks
    arXiv: Signal Processing, 2018
    Co-Authors: Vitaliy Gyrya, Anatoly Zlotnik
    Abstract:

    We present an explicit second order staggered finite difference (FD) discretization scheme for forward simulation of natural gas transport in pipeline networks. By construction, this discretization approach guarantees that the conservation of mass condition is satisfied exactly. The mathematical model is formulated in terms of density, pressure, and mass flux variables, and as a result permits the use of a general equation of state to define the relation between the gas density and pressure for a given temperature. In a single pipe, the model represents the dynamics of the density by propagation of a Non-Linear Wave according to a variable Wave speed. We derive compatibility conditions for linking domain boundary values to enable efficient, explicit simulation of gas flows propagating through a network with pressure changes created by gas compressors. We compare Kiuchi's implicit method and an explicit operator splitting method with our staggered grid method, and perform numerical experiments to validate the convergence order of the new method. In addition, we perform several computations to investigate the influence of non-ideal equation of state models and temperature effects into pipeline simulations with boundary conditions over various time and space scales.

Vitaliy Gyrya - One of the best experts on this subject based on the ideXlab platform.

  • an explicit staggered grid method for numerical simulation of large scale natural gas pipeline networks
    arXiv: Signal Processing, 2018
    Co-Authors: Vitaliy Gyrya, Anatoly Zlotnik
    Abstract:

    We present an explicit second order staggered finite difference (FD) discretization scheme for forward simulation of natural gas transport in pipeline networks. By construction, this discretization approach guarantees that the conservation of mass condition is satisfied exactly. The mathematical model is formulated in terms of density, pressure, and mass flux variables, and as a result permits the use of a general equation of state to define the relation between the gas density and pressure for a given temperature. In a single pipe, the model represents the dynamics of the density by propagation of a Non-Linear Wave according to a variable Wave speed. We derive compatibility conditions for linking domain boundary values to enable efficient, explicit simulation of gas flows propagating through a network with pressure changes created by gas compressors. We compare Kiuchi's implicit method and an explicit operator splitting method with our staggered grid method, and perform numerical experiments to validate the convergence order of the new method. In addition, we perform several computations to investigate the influence of non-ideal equation of state models and temperature effects into pipeline simulations with boundary conditions over various time and space scales.

Eduard P Kontar - One of the best experts on this subject based on the ideXlab platform.

  • large scale simulations of solar type iii radio bursts flux density drift rate duration and bandwidth
    Astronomy and Astrophysics, 2014
    Co-Authors: Heather Ratcliffe, Eduard P Kontar, Hamish A S Reid
    Abstract:

    Non-thermal electrons accelerated in the solar corona can produce intense coherent radio emission, known as solar type III radio bursts. This intense radio emission is often observed from hundreds of MHz in the corona down to the tens of kHz range in interplanetary space. It involves a chain of physical processes from the generation of Langmuir Waves to Non-Linear processes of Wave-Wave interaction. We develop a self-consistent model to calculate radio emission from a non-thermal electron population over a large frequency range, including the effects of electron transport, Langmuir Wave-electron interaction, the evolution of Langmuir Waves due to Non-Linear Wave-Wave interactions, Langmuir Wave conversion into electromagnetic emission, and finally escape of the electromagnetic Waves. For the first time we simulate escaping radio emission over a broad frequency range from 500 MHz down to a few MHz and infer key properties of the radio emission observed: the onset (starting) frequency, identification as fundamental or harmonic emission, peak flux density, instantaneous frequency bandwidth, and timescales for rise and decay. By comparing these large-scale simulations with the observations, we can identify the processes governing the major type III solar radio burst characteristics.

  • large scale simulations of solar type iii radio bursts flux density drift rate duration and bandwidth
    arXiv: Solar and Stellar Astrophysics, 2014
    Co-Authors: Heather Ratcliffe, Eduard P Kontar, Hamish A S Reid
    Abstract:

    Non-thermal electrons accelerated in the solar corona can produce intense coherent radio emission, known as solar type III radio bursts. This intense radio emission is often observed from hundreds of MHz in the corona down to the tens of kHz range in interplanetary space. It involves a chain of physical processes from the generation of Langmuir Waves to nonlinear processes of Wave-Wave interaction. We develop a self-consistent model to calculate radio emission from a non-thermal electron population over large frequency range, including the effects of electron transport, Langmuir Wave-electron interaction, the evolution of Langmuir Waves due to Non-Linear Wave-Wave interactions, Langmuir Wave conversion into electromagnetic emission, and finally escape of the electromagnetic Waves. For the first time we simulate escaping radio emission over a broad frequency range from 500~MHz down to a few MHz and infer key properties of the radio emission observed: the onset (starting) frequency, {identification as fundamental or harmonic emission}, peak flux density, instantaneous frequency bandwidth, and timescales for rise and decay. Comparing with the observations, these large scale simulations enable us to identify the processes governing the key type III solar radio burst characteristics.