Plasma 基本概念 （3）DC Sheath 和RF Sheath - 知乎 - 知乎专栏
Bulk Plasma中的离子从附近阴极sheath的电场获得一部分能量来使阳离子向阴极方向加速。 进入sheath需要kTe/2e 的能量（k-玻尔兹曼常数，Te-电子温度，e-电子电量）。
Sheaths, which are present at essentially any plasma boundary, are one of the most fundamental structures in plasma physics and have been studied extensively.1 Sheaths play the important role of maintaining global current bal-ance, allowing the existence of a quasineutral plasma. At floating boundaries, the sheath is ion rich (an ion sheath),
We emphasize the distinction in the potential structure between the quasi-neutral plasma, a quasi-neutral col lisional pre-sheath and the non-neutral sheath. Very quickly, on the order of the inverse of the plasma frequency, the potential and number distributions reach an equilibrium as the current densities of electrons and ions become equal.
The essential role of the plasma sheath in plasma–liquid …
2021年6月10日 · First, we analyze how the sheath regulates various elementary processes at the plasma–liquid interface, in terms of the electrical coupling, the bidirectional mass transport, and the chemistry between plasma and liquid phase. Next, these three regulatory functions of the sheath are illustrated for concrete applications.
Under most conditions, a very thin negative sheath appears in the vicinity of walls, due to accumulation of electrons on the wall. This is in turn necessitated by the need to reduce the electron flux well below the un-inhibited thermal flux nec ̄e/4, which would lead to very high negative current densities toward the wall.
Sheath Physics | Applications, Theory & Plasma Analysis
2024年5月28日 · Sheath physics is a fundamental aspect of plasma science, playing a pivotal role in both theoretical studies and practical applications. It deals with the study of the sheath, a thin layer where a significant electric field exists, separating a plasma from a solid or liquid surface.
Sheaths and Boundary Layers – Plasma Theory Group
Sheaths act to balance the electron and ion currents lost from a plasma. The most common type of sheath is an ion sheath, meaning it contains more ions than electrons. This is the common situation because ion sheaths act to reflect electrons back into a plasma, while accelerating ions out of the plasma into the material boundary.
plasma sheath (low voltage DC sheath approximation) An electrode or wall in contact with a plasma will usu-ally affect only its immediate surroundings in a plasma. Unless large currents flow in the plasma, or unless it is highly turbulent, a plasma will tend to form a surface sheath to shield itself from applied electric fields. The
sheath is not only recommended, but crucial to an accurate understanding of plasma-liquid interaction. First, we analyze how the sheath regulates various elementary processes at the plasma-liquid interface, in terms of the . lectrical coupling, the bidirectional mass transport and the chemistry between plasma and liqui.
Plasma sheath and beam transport 13 • The plasma potential is one cause of the energy spread of ions extracted from sources • Ions are accelerated through the sheath (to the extraction system, also increases sputtering energy beyond the T i • If the confinement is enhanced or electrons are replaced through