分类： 天文学 >> 天文学 提交时间： 2023-02-19
N. E. Raouafi
L. Matteini
J. Squire
S. T. Badman
M. Velli
K. G. Klein
C. H. K. Chen
W. H. Matthaeus
A. Szabo
M. Linton
R. C. Allen
J. R. Szalay
R. Bruno
R. B. Decker
M. Akhavan-Tafti
O. V. Agapitov
S. D. Bale
R. Bandyopadhyay
K. Battams
L. Berčič
摘要： Launched on 12 Aug. 2018, NASA's Parker Solar Probe had completed 13 of its scheduled 24 orbits around the Sun by Nov. 2022. The mission's primary science goal is to determine the structure and dynamics of the Sun's coronal magnetic field, understand how the solar corona and wind are heated and accelerated, and determine what processes accelerate energetic particles. Parker Solar Probe returned a treasure trove of science data that far exceeded quality, significance, and quantity expectations, leading to a significant number of discoveries reported in nearly 700 peer-reviewed publications. The first four years of the 7-year primary mission duration have been mostly during solar minimum conditions with few major solar events. Starting with orbit 8 (i.e., 28 Apr. 2021), Parker flew through the magnetically dominated corona, i.e., sub-Alfv\'enic solar wind, which is one of the mission's primary objectives. In this paper, we present an overview of the scientific advances made mainly during the first four years of the Parker Solar Probe mission, which go well beyond the three science objectives that are: (1) Trace the flow of energy that heats and accelerates the solar corona and solar wind; (2) Determine the structure and dynamics of the plasma and magnetic fields at the sources of the solar wind; and (3) Explore mechanisms that accelerate and transport energetic particles.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Nour E. Raouafi
G. Stenborg
D. B. Seaton
H. Wang
J. Wang
C. E. DeForest
S. D. Bale
J. F. Drake
V. M. Uritsky
J. T. Karpen
C. R. DeVore
A. C. Sterling
T. S. Horbury
L. K. Harra
S. Bourouaine
J. C. Kasper
P. Kumar
T. D. Phan
M. Velli
摘要： We present EUV solar observations showing evidence for omnipresent jetting activity driven by small-scale magnetic reconnection at the base of the solar corona. We argue that the physical mechanism that heats and drives the solar wind at its source is ubiquitous magnetic reconnection in the form of small-scale jetting activity (i.e., a.k.a. jetlets). This jetting activity, like the solar wind and the heating of the coronal plasma, are ubiquitous regardless of the solar cycle phase. Each event arises from small-scale reconnection of opposite polarity magnetic fields producing a short-lived jet of hot plasma and Alfv\'en waves into the corona. The discrete nature of these jetlet events leads to intermittent outflows from the corona, which homogenize as they propagate away from the Sun and form the solar wind. This discovery establishes the importance of small-scale magnetic reconnection in solar and stellar atmospheres in understanding ubiquitous phenomena such as coronal heating and solar wind acceleration. Based on previous analyses linking the switchbacks to the magnetic network, we also argue that these new observations might provide the link between the magnetic activity at the base of the corona and the switchback solar wind phenomenon. These new observations need to be put in the bigger picture of the role of magnetic reconnection and the diverse form of jetting in the solar atmosphere.
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