A time dependent model for spicule flow

✍ Scribed by S. S. Hasan; P. Venkatakrishnan

• Publisher: Springer
• Year: 1981
• Tongue: English
• Weight: 508 KB
• Volume: 73
• Category: Article
• ISSN: 0038-0938
• DOI: 10.1007/bf00153143

✦ Synopsis

A time dependent model for the flow of gas in a spicule is studied. In this model, the flow occurs in a magnetic flux sheath. Starting from hydrostatic equilibrium, the flux sheath is allowed to collapse normal to itself. The collapse induces a flow of gas along the magnetic field and this flow is identified as a spicule. A variety of sheath geometries and velocity patterns for the normal flow have been studied. It is observed that a large curvature in the field geometry and a large initial value for the normal flow are necessary to achieve spicule-like velocities. The duration for which a large velocity of normal flow is required is much shorter than the average lifetime of a spicule. It is proposed that the initial rapid collapse occurs during an 'impulsive spicule' phase and it is the subsequent gradual relaxation of the flow which is observed as a spicule.