Introductory Thermobaric weapons are classified as a subcomp

Introductory Thermobaric weapons are classified as a subcomponent of a larger family of weapon systems which are commonly known as volumetric weapons. The volumetric weapons include thermobaric and fuel-air explosives (FAE, aerosol bombs in German). The term “thermobaric” is a compound word derived from the Greek words “therme” and “baros” meaning “heat” and “pressure” (implying the effects of temperature and pressure on the target), respectively. The characteristics of this category of weapons are mainly the creation of a large fireball and good blast performance [1]. Both thermobaric and FAE devices operate relying on some similar technical principles. In general, a thermobaric explosive (TBX) consists of a certain central charge (called the core), which is usually a high explosive, and an external secondary charge (fuel-rich formulation). Therefore, the detonation of TBX consists of a dual action: (1) Firstly this crazy idea action (without air oxygen) inside the conventional high explosive core occurs; (2) Then aerobic delayed burning action of the fuel mixture of the outer charge happens which depends mainly on the consumption of the surrounding air [2]. When a shell or projectile containing a fuel in the form of gas, liquid (aerosol) or dust explodes, the fuel or dust-like material is dispersed into the air which forms a cloud. Its occurrence does not depend on an oxidizer being present in the molecule. Then, this cloud is detonated to engender a shock wave, characterized with extended duration that produces overpressure expanding in all directions. In a thermobaric weapon, the fuel consists of a monopropellant and energetic particles [3]. In operation, the aerosol is detonated within a micro/millisecond in a manner similar to a conventional explosive like TNT or RDX. Meanwhile the particles rapidly burn in the surrounding air later in time, thus resulting in an intense fireball and high blast overpressure action. Thermobaric weapons contain monopropellant or secondary explosive and additionally possess elements like B, Al, Si, Ti, Zr and C, mostly [1–5]. After the explosion of the main chargeof a thermobaric/enhanced blast explosive (TBX/EBX) occurs, the post-detonation reaction (namely, burning of Al, etc.) takes plays with air, producing a huge “fireball” within a microsecond. Russia was the first country managed to develop such kind of weapons. RPO-A Schmel rocket, infantry flame-thrower tested successfully in 1984, was the first thermobaric weapon which contained a self-deflagrating mixture consisting of magnesium (Mg) and isopropyl nitrate (IPN). This simple thermobaric explosive produced high devastating pressure wave through the Afghanistan caves and tunnel systems, causing huge damages in the subterranean mazes of the region [4]. The shock waves of conventional explosives are localized and substantially decrease while moving away from the explosion center. Thus, the conventional explosives have quite limited effects on fortified individuals, hiding inside bunkers and/or caves, etc. [5]. Recently, some thermobaric explosives (TBX) which are particularly highly metal-based systems have been successfully designed to exploit the secondary combustion which is responsible for the sustained overpressure and additional thermal effects [6,7]. During the detonation, ideal molecular high explosives (HE) (such as 2,4,6-trinitrotoluene (TNT), cyclo-1,3,5-trimethylene-2,4,6-trinitramine (RDX), pentaerythritol tetranitrate (PETN), and cyclotetramethylene tetranitramine (HMX)) all generate fast decaying blast waves of high peak pressure but very short duration and are mainly designed for either to throw shrapnel and shatter structures and/or penetrate armors. However, their effects are lethal only within their close vicinity and possess obvious undesirable shortcomings for destroying hardened targets such as caves, tunnels, etc. In order to overcome these shortcomings, great efforts have been spent on the development of new weapons which are able to generate higher blast, higher impulse and capable of using its energy not to destroy corners or walls only, but to travel around them efficiently and collapse the hardened targets [8].