Effects of <i>α</i> particles on the angular momentum loss   from the Sun

Li, B.; Li, X.

doi:10.1051/0004-6361:20054624

Cited by 16 publications

(17 citation statements)

References 23 publications

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“…The ratio L k /L M is rather complex and had better be examined case by case due to the presence of terms labeled II in equations (2a) and (2b). Note that terms II derive essentially from the requirement that the protonYalpha-particle velocity difference vector be aligned with the instantaneous magnetic field (Li & Li 2006). The azimuthal speeds are expected to be determined by these terms when there exists a substantial v p; r , which is almost exclusively determined by the way in which the external energy is distributed among different species in the corona.…”

Section: Angular Momentum Loss Rate and Its Distribution Between Partmentioning

confidence: 99%

“…Li & Li's (2006) model was restricted to the region within 1 AU and gave only one solution for the purpose of presenting a general analysis of the angular momentum transport in a threefluid solar wind. In this study we explore, in a quantitative and systematic manner, the interplay between the angular momentum transport and protonYalpha-particle differential streaming in both the slow and fast solar wind for the region extending from the coronal base out to 4.5 AU.…”

Section: Introductionmentioning

confidence: 99%

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Angular Momentum Transport and Proton–Alpha‐Particle Differential Streaming in the Solar Wind

Habbal

2007

ApJ

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The interplay between the protonYalpha-particle differential flow speed, v p , and angular momentum transport in the solar wind is explored by using a three-fluid model. The force introduced by the azimuthal components is found to play an important role in the force balance for ions in interplanetary space, bringing the radial flow speeds of protons and alpha particles closer to each other. For the fast solar wind, the model cannot account for the decrease of v p observed by Helios between 0.3 and 1 AU. However, it can reproduce the v p profile measured by Ulysses beyond 2 AU, if the right value for v p is imposed at that distance. In the slow wind, the effect of solar rotation is more pronounced if one starts with the value measured by Helios at 0.3 AU: a relative change of 10%Y16% is introduced in the radial speed of the alpha particles between 1 and 4 AU. The model calculations show that, although alpha particles consume only a small fraction of the energy and linear momentum fluxes of protons, they cannot be neglected when considering the proton angular momentum flux L p . In most examples, it is found that L p is determined by v p for both the fast and the slow wind. In the slow solar wind, the proton and alpha particle angular momentum fluxes L p and L can be several times larger in magnitude than the flux carried by the magnetic stresses L M . While the sum L P ¼ L p þ L is smaller than L M , for the modeled fast and slow wind alike, this result is at variance with the Helios measurements. Subject headingg s: solar wind -Sun: magnetic fields

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Section: Angular Momentum Loss Rate and Its Distribution Between Partmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Angular Momentum Transport and Proton–Alpha‐Particle Differential Streaming in the Solar Wind

Habbal

2007

ApJ

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“…One of the greatest concerns within the current space science community has been increasingly focused on the Sun‐Earth system, which is intimately linked by the solar wind. The solar wind originates from the chromospheric network [ Xia et al , 2003; Xia , 2003; Xia et al , 2004], according to the measurements of ultraviolet emission and Doppler shifting speed in the inner corona, carries non‐Wentzel‐Kramers‐Brillouin Alfvén Waves in the differential flow of multiple ion species [ Li and Li , 2007, 2008], is very likely driven by an ion cyclotron resonance mechanism via the Kolmogorov turbulent cascade [ Li et al , 2004], and transports the angular momentum from the Sun [ Li and Li , 2006; Li et al , 2007; Li and Li , 2009]. The ubiquitous interplanetary solar wind highly fluctuates, owing to outward emanating disturbances from solar activities.…”

Section: Introductionmentioning

confidence: 99%

Magnetohydrodynamic simulation of the interaction between two interplanetary magnetic clouds and its consequent geoeffectiveness: 2. Oblique collision

2009

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[1] The numerical studies of the interplanetary coupling between multiple magnetic clouds (MCs) are continued by a 2.5-dimensional ideal magnetohydrodynamic (MHD) model in the heliospheric meridional plane. The interplanetary direct collision (DC)/oblique collision (OC) between both MCs results from their same/different initial propagation orientations. Here the OC is explored in contrast to the results of the DC. Both the slow MC1 and fast MC2 are consequently injected from the different heliospheric latitudes to form a compound stream during the interplanetary propagation. The MC1 and MC2 undergo contrary deflections during the process of oblique collision. Their deflection angles of jdq 1 j and jdq 2 j continuously increase until both MC-driven shock fronts are merged into a stronger compound one. The jdq 1 j, jdq 2 j, and total deflection angle Dq (Dq = jdq 1 j + jdq 2 j) reach their corresponding maxima when the initial eruptions of both MCs are at an appropriate angular difference. Moreover, with the increase of MC2's initial speed, the OC becomes more intense, and the enhancement of dq 1 is much more sensitive to dq 2 . The jdq 1 j is generally far less than the jdq 2 j, and the unusual case of jdq 1 j ' jdq 2 j only occurs for an extremely violent OC. But because of the elasticity of the MC body to buffer the collision, this deflection would gradually approach an asymptotic degree. As a result, the opposite deflection between the two MCs, together with the inherent magnetic elasticity of each MC, could efficiently relieve the external compression for the OC in the interplanetary space. Such a deflection effect for the OC case is essentially absent for the DC case. Therefore, besides the magnetic elasticity, magnetic helicity, and reciprocal compression, the deflection due to the OC should be considered for the evolution and ensuing geoeffectiveness of interplanetary interaction among successive coronal mass ejections.Citation: Xiong, M., H. Zheng, and S. Wang (2009), Magnetohydrodynamic simulation of the interaction between two interplanetary magnetic clouds and its consequent geoeffectiveness: 2.

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“…When deriving equation (32b), we have used the fact that U m /B l is a constant. Equations (32a) and (32b) demonstrate a clear connection to the problem of angular momentum transport in a multicomponent solar wind, as has been discussed by Li & Li (2006).…”

Section: The Zero-frequency Limitmentioning

confidence: 62%

“…The equations appropriate for a multicomponent solar wind plasma in the standard five-moment approximation are as follows (for the derivation see Appendix A.1 in Li & Li 2006):…”

Section: Multifluid Equationsmentioning

confidence: 99%

Propagation of Non–Wentzel‐Kramers‐Brillouin Alfven Waves in a Multicomponent Solar Wind with Differential Ion Flow

2007

ApJ

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We investigate the propagation of dissipationless, hydromagnetic, toroidal Alfvén waves in a realistic background, low-latitude fast solar wind with differentially flowing protons and alpha particles. Symmetry about the magnetic axis is assumed. Without invoking the short-wavelength WKB approximation, we derive the equations governing the wave transport from standard five-moment equations. The Alfvénic point, where the combined poloidal Alfvén Mach number M T ¼ 1, is found to be a singular point for the wave equation, which is then numerically solved for three representative angular frequencies ! ¼ 10 À3 , 10 À4 , and 10 À5 rad s À1 , with an amplitude of 10 km s À1 imposed at the coronal base (1 R ). Between 1 R and 1 AU, the numerical solutions show substantial deviation from the WKB expectations. Even for the relatively high frequency ! ¼ 10 À3 rad s À1 , a WKB-like behavior can be seen only in regions r k10 R . For ! ¼ 10 À5 rad s À1 , the computed profiles of wave-related parameters show a spatial dependence distinct from the WKB one, the deviation being particularly pronounced in interplanetary space. In the inner corona r P 4 R , the computed ion velocity fluctuations and wave-induced acceleration exerted on protons or alpha particles are considerably smaller than their WKB counterparts. With the chosen base wave amplitude, the wave acceleration has negligible effect on the ion force balance in the corona. However, at large distances beyond the Alfvénic point, the low-frequency wave with ! ¼ 10 À5 rad s À1 can play an important role in the ion dynamics, with the net effect being to equalize the speeds of the two ion species considered.

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Effects of α particles on the angular momentum loss from the Sun

Cited by 16 publications

References 23 publications

Angular Momentum Transport and Proton–Alpha‐Particle Differential Streaming in the Solar Wind

Angular Momentum Transport and Proton–Alpha‐Particle Differential Streaming in the Solar Wind

Magnetohydrodynamic simulation of the interaction between two interplanetary magnetic clouds and its consequent geoeffectiveness: 2. Oblique collision

Propagation of Non–Wentzel‐Kramers‐Brillouin Alfven Waves in a Multicomponent Solar Wind with Differential Ion Flow

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