Network Heating

Although the Carlsson & Stein model explains the internetwork grains, it is still apparent the network requires an extra heating mechanism. Proposed heating mechanisms can broadly be divided into two categories, namely alternating current (AC) and direct current (DC). Direct current (DC) mechanisms involve current sheets with timescales longer than the dissipation time, whereby the energy stored in the magnetic field is directly dissipated. DC mechanisms can be further subdivided into those which dissipate energy by field aligned currents (Spicer 1991) and those where currents are perpendicular to the field (e.g., nanoflares - Parker 1988). AC mechanisms involve waves which are guided by the magnetic field and dissipated in timescales comparable to the period. These have three common factors, namely the generation, propagation and dissipation of waves. The various modes of waves and how they may influence the plasma through which they propagate are described in the next chapter (also see reviews by Rutten & Uitenbroek 1991; Rutten 1999).