## 1 Introduction  
The process of induced nuclear fission, namely the division of a nucleus into two lighter nuclei, the so-called binary fission (BF), was first proposed by [PERSON] and [PERSON] [1] as an attempt to interpret the data from [PERSON] and [PERSON] [2, 3] who obtained bombarding Uranium with neutrons. The qualitative explanation of the induced fission process was provided within the framework of the Liquid Drop Model (LDM), which was introduced a few years earlier by [PERSON] [4]. In 1939, [PERSON] and [PERSON] formalized [PERSON]'s and [PERSON]'s intuition in their seminal paper [5]. Fission can also take place spontaneously, as was later discovered by [PERSON] and [PERSON] in 1941. In the case of nuclear reactions induced by heavy ions, projectile and target may fuse first to form a compound nucleus (CN), which later on may split into lighter nuclei, the so-called fission fragments, if energetically allowed. Shortly after the discovery of binary fission, the breakup of heavy nuclei into three fragments, ternary fission (TF), was still theoretically predicted on the base of the LDM [6, 7]. LDM calculations involving only the initial and final states indicate that by increasing the CN charge, TF becomes indeed energetically possible. In particular, the energy release is higher than that from BF if the number of fission fragments of fairly equal mass is bigger than 2 [8; 9]. Experimental evidence of TF, consisting of the evidence of long-range alpha particles emitted in connection with spontaneous fission, was first presented by [PERSON] and collaborators [10]. In the same period, ternary and quaternary fission, consisting of the emission of much heavier light fragments with mass up to 32 atomic mass units, was identified by [PERSON], [PERSON], [PERSON], and [PERSON] [11; 12]. Many experimental works have been devoted to the study of spontaneous and neutron-induced fission, i.e., in nuclei, at low excitation energy. In these studies, it has emerged that mostly alpha particles are emitted as a ternary particle (TP) in a plane perpendicular to the fragment separation axis, with some degree of distortion toward the light fragment direction due to the Coulomb focusing of the heavier fragment [13; 14]. Furthermore, the average alpha particle energy is nearly constant, around 16 MeV [15], but disagreement has been reported for the TF/BF ratios, e.g., in the spontaneous fission of \({}^{252}\)Cf \(\approx\) 0.1% [16] and 0.24 \(\pm\) 0.02% [17] were obtained in different measurements. Still, further efforts are necessary to consolidate the present knowledge about ternary fission. By using heavy-ion-induced reactions, heavier nuclei with higher fissility parameters and excitation energies become accessible. This change of the entrance channel conditions largely affects not only the TF but also other competing processes accompanied by alpha-particle emission, for instance, the quasifission and pre-thermalization stages of the formation of the compound nucleus [18; 19; 20]. The analysis of double-differential \(\alpha\) spectra, measured in coincidence with two fission fragments from very heavy composite systems, evidenced alpha multiplicities much larger than those expected from extrapolation of the TF data [18]. These observations support the view that the alpha particles appear from nuclear matter fluctuations occurring in the neck of the fissioning system or from the CN before the scission and cannot be used to probe the potential energy surface (PES) at the scission configuration [21; 22]. The breakup of a nucleus into three fragments of nearly equal mass (\(A_{1}\simeq A_{2}\simeq A_{3}\)) is known as true ternary fission (TTF). This process may occur following one of two different paths, which is to be distinguished experimentally: (i) In one step, known as direct ternary fission (DTF) [23]; (ii) In two subsequent binary breakups, known as sequential ternary fission (STF) [24]. In both cases, three fragments emerge, but the kinematics is expected to be different.