A numerical study of resonant absorption in a magnetohydrodynamic cavity driven by a broadband spectrum

Wright, Andrew N.; Rickard, Graham

doi:10.1086/175620

Cited by 75 publications

(93 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The vortex-like plasma flow structure can excite Alfvén waves at certain frequencies depending on its azimuthal phase velocity. The fast-mode compressional wave acts as an intermediary that transports magnetopause energy of motion to the location of Alfvén resonance (Wright and Rickard 1995). Figure 16 illustrates that as the fast-mode wave propagates within the magnetosphere FLRs are excited.…”

Section: Ulf Waves Driven By the Transient Foreshock Phenomenamentioning

confidence: 99%

The interaction of ultra-low-frequency pc3-5 waves with charged particles in Earth’s magnetosphere

Zong

Rankin

Zhou

2017

Rev. Mod. Plasma Phys.

140

162

View full text Add to dashboard Cite

One of the most important issues in space physics is to identify the dominant processes that transfer energy from the solar wind to energetic particle populations in Earth's inner magnetosphere. Ultra-low-frequency (ULF) waves are an important consideration as they propagate electromagnetic energy over vast distances with little dissipation and interact with charged particles via drift resonance and drift-bounce resonance. ULF waves also take part in magnetosphereionosphere coupling and thus play an essential role in regulating energy flow throughout the entire system. This review summarizes recent advances in the characterization of ULF Pc3-5 waves in different regions of the magnetosphere, including ion and electron acceleration associated with these waves.

show abstract

Section: Ulf Waves Driven By the Transient Foreshock Phenomenamentioning

confidence: 99%

The interaction of ultra-low-frequency pc3-5 waves with charged particles in Earth’s magnetosphere

Zong

Rankin

Zhou

2017

Rev. Mod. Plasma Phys.

140

162

View full text Add to dashboard Cite

show abstract

“…For example, Wright & Rickard (1995) derived two criteria for the efficient excitation of an Alfvén resonance in a cavity driven by a broadband spectrum. Mann et al (1995) considered the excitation of Alfvén waves by fast modes in the magnetospheric cavity and observed that fine scales develop for long times because of phase mixing.…”

Section: Introductionmentioning

confidence: 99%

Coupling of fast and Alfvén waves in a straight bounded magnetic field with density stratification

Arregui¹,

Oliver²,

Ballester³

2003

A&A

View full text Add to dashboard Cite

Abstract. The theoretical understanding of the linear standing or propagating magnetohydrodynamic waves in a variety of solar coronal structures is far from complete since analytical solutions to the linearised MHD equations can only be found for very simple magnetic configurations. In this paper, we use a numerical code to solve the linear fast and Alfvén wave equations in a very simple, bounded magnetic configuration that incorporates two features that are not usually considered in similar works, namely the longitudinal magnetic field component and wave propagation in the longitudinal direction (k y 0). We use a numerical code (Arregui et al. 2001) that has been modified by including a staggered mesh that allows us to properly capture the spatial behaviour of solutions to the wave equations. Coupling between fast and Alfvén modes has been studied in detail and it has been found that it does not take place when the longitudinal field component is zero and the frequency of the fast mode is outside the Alfvén continuum with the same spatial structure along field lines. Under these circumstances, fast modes retain their global spatial behaviour and are also characterised by ω 2 varying linearly with k 2 y , such as in a uniform medium (although here the Alfvén speed changes exponentially in the direction normal to field lines). Regarding mode coupling, its main feature is the blend of fast and Alfvén solutions with close frequencies in some modes with a mixture of their properties, namely discontinuities or jumps around certain magnetic surfaces (such as in pure Alfvén waves), global spatial distribution of the normal velocity component and non-zero density perturbations (such as in fast waves).

show abstract

“…The resonant peak resulting from this energy transfer supplies the small lengthscales necessary for dissipation to become effective (Kuperus et al 1981;Goossens 1991). Numerical results reveal that sideways excitation is most efficient when the loop is driven at the frequency of a fast eigenmode, lying inside the Alfvén continuum, a so-called "quasi-mode" (Poedts et al 1989;Poedts & Kerner 1992;Steinolfson & Davila 1993;Ofman & Davila 1995;Ofman & Davila 1996;Wright & Rickard 1995). Poedts et al (1994) showed that the resonances display a high rate of Ohmic heating compared to the total energy stored in the loop.…”

Section: Introductionmentioning

confidence: 99%

Fast and Alfvén waves driven by azimuthal footpoint motions

Groof

Paes

Goossens

2002

A&A

View full text Add to dashboard Cite

Abstract. The excitation of Alfvén and fast magneto-acoustic waves in coronal loops driven by footpoint motions is studied in linear, ideal MHD. The analysis is restricted to azimuthally polarized footpoint motions so that only Alfvén waves are directly excited which couple to fast magneto-acoustic waves at later times. In the present study a periodic driver is applied at one end of the loop. The effects of a more realistic random driver are studied in the companion paper De Groof & Goossens (2002) (hereafter referred to as Paper II). The first part of the paper is devoted to the study of resonant absorption and phase-mixing in the absence of coupling (azimuthal wavenumber ky = 0). Since the density varies across the loop, resonances occur at the magnetic surfaces where the driving frequency equals the local Alfvén frequency. In a second part where Alfvén waves with ky = 0 coupling to fast waves are taken into account, we find that the behaviour of the MHD waves is strongly dependent on the driving frequency ω d . Especially driving frequencies equal to a quasi-mode frequency seem to make the difference. The fast waves excited in these cases are global oscillations of the system and form quasi-modes as they are damped through the resonant coupling with Alfvén modes. Since these resonances occur at the same location where the original Alfvén wave peaks, the resonant peak is further amplified. While in most cases coupling has a negative effect on the growth of the directly excited Alfvén waves, driving with a quasi-mode frequency leads to a faster growth of the resonant peaks and a more efficient decrease in length scales than in the uncoupled case.

show abstract

A numerical study of resonant absorption in a magnetohydrodynamic cavity driven by a broadband spectrum

Cited by 75 publications

References 0 publications

The interaction of ultra-low-frequency pc3-5 waves with charged particles in Earth’s magnetosphere

The interaction of ultra-low-frequency pc3-5 waves with charged particles in Earth’s magnetosphere

Coupling of fast and Alfvén waves in a straight bounded magnetic field with density stratification

Fast and Alfvén waves driven by azimuthal footpoint motions

Contact Info

Product

Resources

About