C. Kennel - Academia.edu (original) (raw)

Papers by C. Kennel

Research paper thumbnail of Alfvén shock trains

Physics of Fluids B: Plasma Physics, 1991

The Cohen–Kulsrud–Burgers equation (CKB) is used to consider the nonlinear evolution of resistive... more The Cohen–Kulsrud–Burgers equation (CKB) is used to consider the nonlinear evolution of resistive, quasiparallel Alfvén waves subject to a long-wavelength, plane-polarized, monochromatic instability. The instability saturates by nonlinear steepening, which proceeds until the periodic waveform develops an interior scale length comparable to the dissipation length; a fast or an intermediate shock then forms. The result is a periodic train of Alfvén shocks of one or the other type. For propagation strictly parallel to the magnetic field, there will be two shocks per instability wavelength. Numerical integration of the time-dependent CKB equation shows that an initial, small-amplitude growing wave asymptotes to a stable, periodic stationary wave whose analytic solution specifies how the type of shock embedded in the shock train, and the amplitude and speed of the shock train, depend on the strength and phase of the instability. Waveforms observed upstream of the Earth’s bowshock and com...

Research paper thumbnail of Fate of mountain glaciers in the anthropocene

Research paper thumbnail of Formation and regular dynamics of shock-trains in the Burgers model

Physica D: Nonlinear Phenomena, 1995

Abstract Solutions to the Burgers equation with small viscosity and a periodic driving force are ... more Abstract Solutions to the Burgers equation with small viscosity and a periodic driving force are considered. A class of traveling wave solutions is investigated by means of a linearizing transformation as well as asymptotic methods that can be applied to more general nonlinear equations. Using these techniques, travelling wave solutions are obtained for the case where the driving term represents the loss of stability of two harmonics in the spectrum. Numerical integration shows that the time-asymptotic behaviour reduces entirely to a dynamical system of periodic shock-train solutions originating from these two unstable harmonics. The stability of the solutions in the range of parameters where they represent a travelling waves is briefly considered.

Research paper thumbnail of Atmospheric Physics

Research paper thumbnail of Cold Upper Hybrid and Multicyclotron Harmonic Instabilities

Research paper thumbnail of After Columbia, a new NASA?

Research paper thumbnail of Low-Frequency Whistler Mode

Physics of Fluids, 1966

ABSTRACT

Research paper thumbnail of Coping with Uncertainty in Space Science Planning

Research paper thumbnail of Stably trapped proton limits for Jupiter(Pitch-angle diffusion and stably trapped limits for protons in Earth and Jupiter magnetospheres)

Research paper thumbnail of Plasma waves at collisionless shocks in space-The observations of Frederick L. Scarf

Research paper thumbnail of Stably trapped proton limits for Jupiter

Research paper thumbnail of Knowledge Action Networks: Connecting Regional Climate Change Assessments to Local Action

Title: Knowledge Action Networks: Connecting regional climate change assessments to local action ... more Title: Knowledge Action Networks: Connecting regional climate change assessments to local action ... Author: Kennel, Charles, Sustainability Solutions Institute and Scripps Institution of Oceanography, University of California, San Diego; Global Water Initiative, University of ...

Research paper thumbnail of Stationary electrostatic solitary waves in the auroral plasma

Geophysical Monograph Series, 2000

ABSTRACT

Research paper thumbnail of Structure and evolution of time-dependent intermediate shocks

Physical Review Letters, 1992

ABSTRACT

Research paper thumbnail of Evidence for a magnetosphere at Ganymede from plasma-wave observations by the Galileo spacecraft

Research paper thumbnail of The beta dependence of the collisionless tearing instability at the dayside magnetopause

Journal of Geophysical Research, 1992

ABSTRACT

Research paper thumbnail of The role of intermediate shocks in magnetic reconnection

Geophysical Research Letters, 1992

ABSTRACT

Research paper thumbnail of Particle tracing in the magnetosphere: New algorithms and results

Geophysical Research Letters, 1993

We use a fast, efficient method to trace charged particles through realistic magnetospheric elect... more We use a fast, efficient method to trace charged particles through realistic magnetospheric electric and magnetic fields, greatly reducing computer simulation times. The method works for particles having arbitrary charge, energy, or pitch angle but which conserve the first two adiabatic invariants. We also apply an efficient method of classifying drift orbits, which greatly simplifies the task of identifying the last closed drift path or other drift boundaries. Finally, we calculate the time-independent evolution of the bounce-averaged phase space density along convective drift orbits. With these three tools, convective evolution of the particle distribution from the tail can now be described quantitatively, an essential step in understanding the production of unstable distributions in the magnetosphere. One can also categorize topologically different drift orbits, which is necessary to understand the unique particle signatures of the convecting plasma such as Alfvdn layers and the plasmapause. These signatures can then be used to extract the electric and magnetic fields or to test the validity of the model fields. The method is particularly appropriate for particles in the energy range 0.01<E<100 keV, which are influenced by both electric and magnetic fields, and for time periods without invariant destroying waves.

Research paper thumbnail of Structural relations for time-dependent intermediate shocks

Geophysical Research Letters, 1992

ABSTRACT

Research paper thumbnail of The electromagnetic interchange mode in a partially ionized collisional plasma(spread F region)

A collisional electromagnetic dispersion relation is derived from two-fluid theory for the interc... more A collisional electromagnetic dispersion relation is derived from two-fluid theory for the interchange mode coupled to the Alfven, acoustic, drift and entropy modes in a partially ionized plasma. The fundamental electromagnetic nature of the interchange model is noted; coupling to the intermediate Alfven mode is strongly stabilizing for finite k sub z. Both ion viscous and ion-neutral stabilization are included, and it was found that collisions destroy the ion finite Larmor radius cutoff at short perpendicular wavelengths.

Research paper thumbnail of Alfvén shock trains

Physics of Fluids B: Plasma Physics, 1991

The Cohen–Kulsrud–Burgers equation (CKB) is used to consider the nonlinear evolution of resistive... more The Cohen–Kulsrud–Burgers equation (CKB) is used to consider the nonlinear evolution of resistive, quasiparallel Alfvén waves subject to a long-wavelength, plane-polarized, monochromatic instability. The instability saturates by nonlinear steepening, which proceeds until the periodic waveform develops an interior scale length comparable to the dissipation length; a fast or an intermediate shock then forms. The result is a periodic train of Alfvén shocks of one or the other type. For propagation strictly parallel to the magnetic field, there will be two shocks per instability wavelength. Numerical integration of the time-dependent CKB equation shows that an initial, small-amplitude growing wave asymptotes to a stable, periodic stationary wave whose analytic solution specifies how the type of shock embedded in the shock train, and the amplitude and speed of the shock train, depend on the strength and phase of the instability. Waveforms observed upstream of the Earth’s bowshock and com...

Research paper thumbnail of Fate of mountain glaciers in the anthropocene

Research paper thumbnail of Formation and regular dynamics of shock-trains in the Burgers model

Physica D: Nonlinear Phenomena, 1995

Abstract Solutions to the Burgers equation with small viscosity and a periodic driving force are ... more Abstract Solutions to the Burgers equation with small viscosity and a periodic driving force are considered. A class of traveling wave solutions is investigated by means of a linearizing transformation as well as asymptotic methods that can be applied to more general nonlinear equations. Using these techniques, travelling wave solutions are obtained for the case where the driving term represents the loss of stability of two harmonics in the spectrum. Numerical integration shows that the time-asymptotic behaviour reduces entirely to a dynamical system of periodic shock-train solutions originating from these two unstable harmonics. The stability of the solutions in the range of parameters where they represent a travelling waves is briefly considered.

Research paper thumbnail of Atmospheric Physics

Research paper thumbnail of Cold Upper Hybrid and Multicyclotron Harmonic Instabilities

Research paper thumbnail of After Columbia, a new NASA?

Research paper thumbnail of Low-Frequency Whistler Mode

Physics of Fluids, 1966

ABSTRACT

Research paper thumbnail of Coping with Uncertainty in Space Science Planning

Research paper thumbnail of Stably trapped proton limits for Jupiter(Pitch-angle diffusion and stably trapped limits for protons in Earth and Jupiter magnetospheres)

Research paper thumbnail of Plasma waves at collisionless shocks in space-The observations of Frederick L. Scarf

Research paper thumbnail of Stably trapped proton limits for Jupiter

Research paper thumbnail of Knowledge Action Networks: Connecting Regional Climate Change Assessments to Local Action

Title: Knowledge Action Networks: Connecting regional climate change assessments to local action ... more Title: Knowledge Action Networks: Connecting regional climate change assessments to local action ... Author: Kennel, Charles, Sustainability Solutions Institute and Scripps Institution of Oceanography, University of California, San Diego; Global Water Initiative, University of ...

Research paper thumbnail of Stationary electrostatic solitary waves in the auroral plasma

Geophysical Monograph Series, 2000

ABSTRACT

Research paper thumbnail of Structure and evolution of time-dependent intermediate shocks

Physical Review Letters, 1992

ABSTRACT

Research paper thumbnail of Evidence for a magnetosphere at Ganymede from plasma-wave observations by the Galileo spacecraft

Research paper thumbnail of The beta dependence of the collisionless tearing instability at the dayside magnetopause

Journal of Geophysical Research, 1992

ABSTRACT

Research paper thumbnail of The role of intermediate shocks in magnetic reconnection

Geophysical Research Letters, 1992

ABSTRACT

Research paper thumbnail of Particle tracing in the magnetosphere: New algorithms and results

Geophysical Research Letters, 1993

We use a fast, efficient method to trace charged particles through realistic magnetospheric elect... more We use a fast, efficient method to trace charged particles through realistic magnetospheric electric and magnetic fields, greatly reducing computer simulation times. The method works for particles having arbitrary charge, energy, or pitch angle but which conserve the first two adiabatic invariants. We also apply an efficient method of classifying drift orbits, which greatly simplifies the task of identifying the last closed drift path or other drift boundaries. Finally, we calculate the time-independent evolution of the bounce-averaged phase space density along convective drift orbits. With these three tools, convective evolution of the particle distribution from the tail can now be described quantitatively, an essential step in understanding the production of unstable distributions in the magnetosphere. One can also categorize topologically different drift orbits, which is necessary to understand the unique particle signatures of the convecting plasma such as Alfvdn layers and the plasmapause. These signatures can then be used to extract the electric and magnetic fields or to test the validity of the model fields. The method is particularly appropriate for particles in the energy range 0.01<E<100 keV, which are influenced by both electric and magnetic fields, and for time periods without invariant destroying waves.

Research paper thumbnail of Structural relations for time-dependent intermediate shocks

Geophysical Research Letters, 1992

ABSTRACT

Research paper thumbnail of The electromagnetic interchange mode in a partially ionized collisional plasma(spread F region)

A collisional electromagnetic dispersion relation is derived from two-fluid theory for the interc... more A collisional electromagnetic dispersion relation is derived from two-fluid theory for the interchange mode coupled to the Alfven, acoustic, drift and entropy modes in a partially ionized plasma. The fundamental electromagnetic nature of the interchange model is noted; coupling to the intermediate Alfven mode is strongly stabilizing for finite k sub z. Both ion viscous and ion-neutral stabilization are included, and it was found that collisions destroy the ion finite Larmor radius cutoff at short perpendicular wavelengths.