相对论质子束在等离子体中的丝化现象。

Filamentation of a relativistic proton bunch in plasma.

作者信息

Verra L, Amoedo C, Torrado N, Clairembaud A, Mezger J, Pannell F, Pucek J, van Gils N, Bergamaschi M, Zevi Della Porta G, Lopes N, Sublet A, Turner M, Gschwendtner E, Muggli P, Agnello R, Ahdida C C, Andrebe Y, Apsimon O, Apsimon R, Arnesano J M, Bencini V, Blanchard P, Burrows P N, Buttenschön B, Caldwell A, Chung M, Cooke D A, Davut C, Demeter G, Dexter A C, Doebert S, Farmer J, Fasoli A, Fonseca R, Furno I, Granados E, Granetzny M, Graubner T, Grulke O, Guran E, Henderson J, Kedves M Á, Kraus F, Krupa M, Lefevre T, Liang L, Liu S, Lotov K, Martinez Calderon M, Mazzoni S, Moon K, Morales Guzmán P I, Moreira M, Nechaeva T, Okhotnikov N, Pakuza C, Pardons A, Pepitone K, Poimendidou E, Pukhov A, Ramjiawan R L, Ranc L, Rey S, Rossel R, Saberi H, Schmitz O, Senes E, Silva F, Silva L, Spear B, Stollberg C, Swain C, Topaloudis A, Tuev P, Velotti F, Verzilov V, Vieira J, Walter E, Welsch C, Wendt M, Wing M, Wolfenden J, Woolley B, Xia G, Yarygova V, Zepp M

机构信息

Ecole Polytechnique Federale de Lausanne (EPFL), Swiss Plasma Center (SPC), 1015 Lausanne, Switzerland.

CERN, 1211 Geneva 23, Switzerland.

出版信息

Phys Rev E. 2024 May;109(5-2):055203. doi: 10.1103/PhysRevE.109.055203.

DOI:10.1103/PhysRevE.109.055203

PMID:38907424

Abstract

We show in experiments that a long, underdense, relativistic proton bunch propagating in plasma undergoes the oblique instability, which we observe as filamentation. We determine a threshold value for the ratio between the bunch transverse size and plasma skin depth for the instability to occur. At the threshold, the outcome of the experiment alternates between filamentation and self-modulation instability (evidenced by longitudinal modulation into microbunches). Time-resolved images of the bunch density distribution reveal that filamentation grows to an observable level late along the bunch, confirming the spatiotemporal nature of the instability. We provide a rough estimate of the amplitude of the magnetic field generated in the plasma by the instability and show that the associated magnetic energy increases with plasma density.

摘要

我们在实验中表明，在等离子体中传播的长的、低密度的相对论质子束会经历斜向不稳定性，我们将其观测为丝状化。我们确定了不稳定性发生时束团横向尺寸与等离子体趋肤深度之比的阈值。在阈值处，实验结果在丝状化和自调制不稳定性（由纵向调制为微束团证明）之间交替。束团密度分布的时间分辨图像显示，丝状化在束团传播后期发展到可观测水平，证实了不稳定性的时空特性。我们对不稳定性在等离子体中产生的磁场振幅进行了粗略估计，并表明相关的磁能随等离子体密度增加。