太陽風の終結ショックを非熱イオンによって媒介する
R B Decker1, S M Krimigis, E C Roelof
1The Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland 20723, USA. robert.decker@jhuapl.edu
Nature
|July 4, 2008
まとめ
ヘリオシェアの高エネルギーイオンは,太陽風の終結ショックを著しく影響する. 旅行者2号によって検出されたこれらの非熱イオンが,衝撃構造とエネルギー転送を制御します.
科学分野:
- 宇宙物理学 宇宙物理学
- ヘリオフィジックス ヘリオフィジックス
- プラズマ物理学 プラズマ物理学
背景:
- 太陽風の終結ショックは,太陽風のプラズマが減速する領域です.
- ボイジャー1号とボイジャー2号の宇宙船は,以前,太陽風と太陽の粒子を測定していた.
- ショックトランジション物理学におけるこれらの粒子の役割は不明のままでした.
研究 の 目的:
- 終結ショックとヘリオシートダイナミクスに対する非熱粒子の影響を調査する.
- プラズマと磁場データを分析するために,ボイジャー2の衝撃交差点から.
主な方法:
- "ボイジャー2"宇宙船からのプラズマと磁場機器のデータを活用した.
- 分析された粒子の強度測定,特に低エネルギーイオン (>0.028 MeV).
- 非熱イオン圧力を熱プラズマと磁場圧力と比較した.
主要な成果:
- ボイジャー2号は,終結ショックの両側に高強度の非熱イオンと電子を検出しました.
- ヘリオシート内の非熱イオン圧力は,熱プラズマと磁場圧力と比べられるか,それ以上であることが判明しました.
- これらの低エネルギーイオンは,ターミネーションショック構造において重要な役割を果たします.
結論:
- 非熱的イオン分布は,終結ショックとヘリオシートにおけるダイナミックなプロセスの鍵です.
- これらのイオンの加速は,太陽風の大量流動運動エネルギーの重要な部分を抽出します.
- これらの発見は,ターミネーションショックの物理にエネルギーのある粒子が与える影響を明らかにします.
関連する概念動画
Momentum And Radiation Pressure
2.6K
An object absorbing an electromagnetic wave would experience a force in the direction of propagation of the wave. This force occurs because electromagnetic waves contain and transport momentum. The force accounts for the wave's radiation pressure exerted on the object. Maxwell's prediction was confirmed in 1903 by Nichols and Hull by precisely measuring radiation pressures with a torsion balance. The measuring instrument had mirrors suspended from a fiber kept inside a glass container.
2.6K
Radiation Pressure: Problem Solving
977
The radiation pressure applied by an electromagnetic wave on a perfectly absorbing surface equals the energy density of the wave. The wave's momentum also gets transferred to the surface when an electromagnetic wave is entirely absorbed by it. The rate at which momentum is transmitted to an absorbing surface perpendicular to the propagation direction equals the force on the surface.
The average value of the rate of momentum transfer divided by the absorbing area represents the average force...
The average value of the rate of momentum transfer divided by the absorbing area represents the average force...
977
Magnetostatic Boundary Conditions
1.8K
An electric field suffers a discontinuity at a surface charge. Similarly, a magnetic field is discontinuous at a surface current. The perpendicular component of a magnetic field is continuous across the interface of two magnetic mediums. In contrast, its parallel component, perpendicular to the current, is discontinuous by the amount equal to the product of the vacuum permeability and the surface current. Like the scalar potential in electrostatics, the vector potential is also continuous...
1.8K
Precipitation of Ions
31.2K
Predicting Precipitation
The equation that describes the equilibrium between solid calcium carbonate and its solvated ions is:
The equation that describes the equilibrium between solid calcium carbonate and its solvated ions is:
31.2K
Formation of Complex Ions
26.8K
A type of Lewis acid-base chemistry involves the formation of a complex ion (or a coordination complex) comprising a central atom, typically a transition metal cation, surrounded by ions or molecules called ligands. These ligands can be neutral molecules like H2O or NH3, or ions such as CN− or OH−. Often, the ligands act as Lewis bases, donating a pair of electrons to the central atom. These types of Lewis acid-base reactions are examples of a broad subdiscipline called coordination...
26.8K
Electrostatic Boundary Conditions
1.1K
Consider an external electric field propagating through a homogeneous medium. When the electric field crosses the surface boundary of the medium, it undergoes a discontinuity. The electric field can be resolved into normal and tangential components. The amount by which the field changes at any boundary is given by the difference between the field components above and below the surface boundary.
The surface integral of an electric field is given by Gauss's law in integral form and is related to...
The surface integral of an electric field is given by Gauss's law in integral form and is related to...
1.1K


