The ballooning instability (a.k.a. ballooning mode instability) is a type of internal pressure-driven plasma instability usually seen in tokamak fusion power reactors[1] or in space plasmas.[2] It is important in fusion research as it determines a set of criteria for the maximum achievable plasma beta.[3] The name refers to the shape and action of the instability, which acts like the elongations formed in a long balloon when it is squeezed. In literature, the structure of these elongations are commonly referred to as 'fingers'.[4][5][6]
The narrow fingers of plasma produced by the instability are capable of accelerating and pushing aside the surrounding magnetic field in order to cause a sudden, explosive release of energy. Thus, the instability is also known as the explosive instability.[7][8][9]
The interchange instability can be derived from the equations of the ballooning instability as a special case in which the ballooning mode does not perturb the equilibrium magnetic field.[2] This special limit is known as the Mercier criterion.[3]
{{cite book}}
: CS1 maint: multiple names: authors list (link)