%0 Journal Article %T Inferring possible magnetic field strength of accreting inflows in EXor-type objects from scaled laboratory experiments %+ Laboratoire pour l'utilisation des lasers intenses (LULI) %+ Institute of Applied Physics of RAS %+ Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA) %+ INAF - Osservatorio Astronomico di Palermo (OAPa) %+ INAF - Osservatorio Astronomico di Roma (OAR) %+ Università degli studi di Palermo - University of Palermo %+ Laboratoire national des champs magnétiques intenses - Toulouse (LNCMI-T) %+ Horia Hulubei National Institute for Physics and Nuclear Engineering %+ Moscow State Engineering Physics Institute (MEPhI) %+ Joint Institute for High Temperatures of the RAS (JIHT) %+ The National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) [Moscow, Russia] %A Burdonov, K. %A Bonito, R. %A Giannini, T. %A Aidakina, N. %A Argiroffi, C. %A Béard, Jérome %A Chen, S. N. %A Ciardi, A. %A Ginzburg, V. %A Gubskiy, K. %A Gundorin, V. %A Gushchin, M. %A Kochetkov, A. %A Korobkov, S. %A Kuzmin, A. %A Kuznetsov, A. %A Pikuz, S. %A Revet, G. %A Ryazantsev, S. %A Shaykin, A. %A Shaykin, I. %A Soloviev, A. %A Starodubtsev, M. %A Strikovskiy, A. %A Yao, W. %A Yakovlev, I. %A Zemskov, R. %A Zudin, I. %A Khazanov, E. %A Orlando, S. %A Fuchs, J. %Z This work was partly done within the LABEX Plas@Par, the DIM ACAV funded by the Region Ile-de-France, and supported by Grant No. 11-IDEX- 0004-02 from ANR %Z . The research leading to these results is supported by Extreme Light Infrastructure Nuclear Physics (ELINP) Phase II, a project co-financed by the Romanian Government and European Union through the European Regional Development Fund, and by the project ELI-RO-2020-23 funded by IFA (Romania). %< avec comité de lecture %@ 0004-6361 %J Astronomy and Astrophysics - A&A %I EDP Sciences %V 648 %P A81 %8 2021-04 %D 2021 %Z 2102.08156 %Z 2021A&A...648A..81B %R 10.1051/0004-6361/202040036 %K accretion %K accretion disks %K instabilities %K magnetohydrodynamics (MHD) %K stars: pre-main sequence %K shock waves %K stars: individual: V1118 Ori %Z Physics [physics] %Z Physics [physics]/Astrophysics [astro-ph]Journal articles %X Aims. EXor-type objects are protostars that display powerful UV-optical outbursts caused by intermittent and powerful events of magnetospheric accretion. These objects are not yet well investigated and are quite difficult to characterize. Several parameters, such as plasma stream velocities, characteristic densities, and temperatures, can be retrieved from present observations. As of yet, however, there is no information about the magnetic field values and the exact underlying accretion scenario is also under discussion.Methods. We use laboratory plasmas, created by a high power laser impacting a solid target or by a plasma gun injector, and make these plasmas propagate perpendicularly to a strong external magnetic field. The propagating plasmas are found to be well scaled to the presently inferred parameters of EXor-type accretion event, thus allowing us to study the behaviour of such episodic accretion processes in scaled conditions.Results. We propose a scenario of additional matter accretion in the equatorial plane, which claims to explain the increased accretion rates of the EXor objects, supported by the experimental demonstration of effective plasma propagation across the magnetic field. In particular, our laboratory investigation allows us to determine that the field strength in the accretion stream of EXor objects, in a position intermediate between the truncation radius and the stellar surface, should be of the order of 100 G. This, in turn, suggests a field strength of a few kilogausses on the stellar surface, which is similar to values inferred from observations of classical T Tauri stars. %G English %2 https://cea.hal.science/cea-03200871/document %2 https://cea.hal.science/cea-03200871/file/aa40036-20.pdf %L cea-03200871 %U https://cea.hal.science/cea-03200871 %~ OBSPM %~ CEA %~ INSU %~ X %~ ENS-PARIS %~ UNIV-TLSE3 %~ UGA %~ CNRS %~ UNIV-CERGY %~ INSA-TOULOUSE %~ LERMA %~ X-LULI %~ X-DEP %~ X-DEP-PHYS %~ OPENAIRE %~ PSL %~ LNCMI %~ INSA-GROUPE %~ SORBONNE-UNIVERSITE %~ SORBONNE-UNIV %~ SU-SCIENCES %~ IP_PARIS %~ IP_PARIS_COPIE %~ TEST-HALCNRS %~ ENS-PSL %~ OBSPM-PSL %~ UGA-EPE %~ SU-TI %~ FERMI %~ ALLIANCE-SU %~ UNIV-UT3 %~ UT3-INP %~ UT3-TOULOUSEINP