Radial Evolution of Sunward Strahl Electrons in the Inner Heliosphere

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68378289%3A_____%2F20%3A00536256" target="_blank" >RIV/68378289:_____/20:00536256 - isvavai.cz</a>

Výsledek na webu

<a href="https://doi.org/10.1007/s11207-019-1579-3" target="_blank" >https://doi.org/10.1007/s11207-019-1579-3</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1007/s11207-019-1579-3" target="_blank" >10.1007/s11207-019-1579-3</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Radial Evolution of Sunward Strahl Electrons in the Inner Heliosphere

Popis výsledku v původním jazyce

The heliospheric magnetic field (HMF) exhibits local inversions, in which the field apparently ´bends back´ upon itself. Candidate mechanisms to produce these inversions include various configurations of upstream interchange reconnection: either in the heliosphere, or in the corona where the solar wind is formed. Explaining the source of these inversions, and how they evolve in time and space, is thus an important step towards explaining the origins of the solar wind. Inverted heliospheric magnetic field lines can be identified by the anomalous sunward (i.e. inward) streaming of the typically anti-sunward propagating, field-aligned (or anti-aligned), beam of electrons known as the ´strahl´. We test if the pitch angle distribution (PAD) properties of sunward-propagating strahl are different from those of outward strahl. We perform a statistical study of strahl observed by the Helios spacecraft, over heliocentric distances spanning approximate to 0.3 - 1 AU. We find that sunward strahl PADs are broader and less intense than their outward directed counterparts: particularly at distances 0.3 - 0.75 AU. This is consistent with sunward strahl being subject to additional, path-length dependent, scattering in comparison to outward strahl. We conclude that the longer and more variable path from the Sun to the spacecraft, along inverted magnetic field, leads to this additional scattering. The results also suggest that the relative importance of scattering along this additional path length drops off with heliocentric distance. These results can be explained by a relatively simple, constant-rate, scattering process.

Název v anglickém jazyce

Radial Evolution of Sunward Strahl Electrons in the Inner Heliosphere

Popis výsledku anglicky

The heliospheric magnetic field (HMF) exhibits local inversions, in which the field apparently ´bends back´ upon itself. Candidate mechanisms to produce these inversions include various configurations of upstream interchange reconnection: either in the heliosphere, or in the corona where the solar wind is formed. Explaining the source of these inversions, and how they evolve in time and space, is thus an important step towards explaining the origins of the solar wind. Inverted heliospheric magnetic field lines can be identified by the anomalous sunward (i.e. inward) streaming of the typically anti-sunward propagating, field-aligned (or anti-aligned), beam of electrons known as the ´strahl´. We test if the pitch angle distribution (PAD) properties of sunward-propagating strahl are different from those of outward strahl. We perform a statistical study of strahl observed by the Helios spacecraft, over heliocentric distances spanning approximate to 0.3 - 1 AU. We find that sunward strahl PADs are broader and less intense than their outward directed counterparts: particularly at distances 0.3 - 0.75 AU. This is consistent with sunward strahl being subject to additional, path-length dependent, scattering in comparison to outward strahl. We conclude that the longer and more variable path from the Sun to the spacecraft, along inverted magnetic field, leads to this additional scattering. The results also suggest that the relative importance of scattering along this additional path length drops off with heliocentric distance. These results can be explained by a relatively simple, constant-rate, scattering process.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10308 - Astronomy (including astrophysics,space science)

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2020

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Solar Physics

ISSN

0038-0938

e-ISSN

—

Svazek periodika

295

Číslo periodika v rámci svazku

2

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

26

Strana od-do

16

Kód UT WoS článku

000519632300003

EID výsledku v databázi Scopus

2-s2.0-85078285010