Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title> <jats:p> <jats:italic>Voyager 1</jats:italic> observed Kolmogorov-like (<jats:italic>k</jats:italic> <jats:sup>−5/3</jats:sup>) compressible turbulence just upwind of the heliopause. Subsequent measurements by <jats:italic>Voyager 1</jats:italic> further from the heliopause revealed that the observed fluctuations were now fully incompressible, with a <jats:italic>k</jats:italic> <jats:sup>−5/3</jats:sup> spectrum that was essentially identical to that of the earlier compressible spectrum. Zank et al. showed that only compressible fast magnetosonic modes could be transmitted from the inner heliosheath into the very local interstellar medium (VLISM), and could exhibit a <jats:italic>k</jats:italic> <jats:sup>−5/3</jats:sup> spectrum. We show here that the small plasma beta VLISM admits three-wave interactions between a fast magnetosonic mode, a zero-frequency mode, and an Alfvén wave. The fast magnetosonic mode is converted to an incompressible Alfvén (or zero-frequency) mode with wavenumber almost identical to that of the initial compressible fast mode. The initial compressible and generated incompressible spectra are essentially identical. For the wavelength range observed by <jats:italic>Voyager 1</jats:italic>, we estimate that compressible fast modes are fully mode-converted to incompressible fluctuations within ∼10 au of the heliopause. We suggest that the VLISM magnetic field spectrum is a superposition of a higher amplitude ∼<jats:italic>k</jats:italic> <jats:sup>−5/3</jats:sup> spectrum of heliospheric origin with an estimated correlation length ∼30 au, having a minimum wavenumber ∼(100)<jats:sup>−1</jats:sup> (au)<jats:sup>−1</jats:sup>, and a lower amplitude (possibly local) ISM <jats:italic>k</jats:italic> <jats:sup>−5/3</jats:sup> spectrum, the latter possessing an outer scale ≥2 pc. We suggest that the transmission of compressible turbulence from an inner asterosheath into the local circumstellar interstellar medium surrounding a star, and the subsequent mode conversion to incompressible turbulence, may be a general mechanism by which stars drive turbulence in the interstellar medium.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>This paper considers the concept of wave-particle thermodynamic equilibrium in order to improve our understanding of the role of turbulent heating in the solar wind proton plasma. The thermodynamic equilibrium in plasmas requires the energy of a plasmon—the quantum of plasma fundamental oscillation—to be balanced by the proton-magnetized plasma energy, that is, the magnetic field and proton kinetic/thermal energy. This equilibrium has already been confirmed in several prior analyses, but also in this paper, by analyzing (i) multi-spacecraft data sets along the radial profile of the inner heliosphere, and (ii) representative data sets of a variety of 27 different space and astrophysical plasmas. Recently, it was shown that the slow mode of the near-Earth solar wind plasma is characterized by a missing energy source that is necessary for keeping the energy balance in the plasmon–proton-magnetized plasma. Here we show strong evidence that this missing energy is the turbulent energy heating the solar wind. In particular, we derive and compare the radial and velocity profiles of this missing energy and the turbulent energy in the inner heliosphere, also considering other minor contributions, such as the temperature of pickup protons. The connection of the missing plasmon–proton energy with the turbulent energy provides a new method for estimating and cross-examining the turbulent energy in space and astrophysical plasmas, while it confirms the universality of the involved new Planck-type constant that implies a large-scale quantization.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>So far, most studies on the structure of coronal mass ejections (CMEs) are conducted through white-light coronagraphs, demonstrating that about one third of CMEs exhibit the typical three-part structure in the high corona (e.g., beyond 2 <jats:inline-formula> <jats:tex-math> <?CDATA ${R}_{\odot }$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjab50b6ieqn1.gif" xlink:type="simple" /> </jats:inline-formula>), i.e., the bright front, the dark cavity, and the bright core. In this paper, we address the CME structure in the low corona (e.g., below 1.3 <jats:inline-formula> <jats:tex-math> <?CDATA ${R}_{\odot }$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjab50b6ieqn2.gif" xlink:type="simple" /> </jats:inline-formula>) through extreme-ultraviolet (EUV) passbands and find that the three-part CMEs in the white-light images can possess a similar three-part appearance in the EUV images, i.e., a leading edge, a low-density zone, and a filament or hot channel. The analyses identify that the leading edge and the filament or hot channel in the EUV passbands evolve into the front and the core later within several solar radii in the white-light passbands, respectively. What is more, we find that the CMEs without an obvious cavity in the white-light images can also exhibit the clear three-part appearance in the EUV images, which means that the low-density zone in the EUV images (observed as the cavity in white-light images) can be compressed and/or transformed gradually by the expansion of the bright core and/or the reconnection of the magnetic field surrounding the core during the CME propagation outward. Our study suggests that more CMEs can possess the clear three-part structure in their early eruption stage. The nature of the low-density zone between the leading edge and the filament or hot channel is discussed.</jats:p>