Abstract
Forecasting the arrival time of coronal mass ejections (CMEs) and their associated shocks is one of the key aspects of space weather research. One of the commonly used models is the analytical drag-based model (DBM) for heliospheric propagation of CMEs due to its simplicity and calculation speed. The DBM relies on the observational fact that slow CMEs accelerate whereas fast CMEs decelerate and is based on the concept of magnetohydrodynamic (MHD) drag, which acts to adjust the CME speed to the ambient solar wind. Although physically DBM is applicable only to the CME magnetic structure, it is often used as a proxy for shock arrival. In recent years, the DBM equation has been used in many studies to describe the propagation of CMEs and shocks with different geometries and assumptions. In this study, we provide an overview of the five DBM versions currently available and their respective tools, developed at Hvar Observatory and frequently used by researchers and forecasters (1) basic 1D DBM, a 1D model describing the propagation of a single point (i.e., the apex of the CME) or a concentric arc (where all points propagate identically); (2) advanced 2D self-similar cone DBM, a 2D model which combines basic DBM and cone geometry describing the propagation of the CME leading edge which evolves in a self-similar manner; (3) 2D flattening cone DBM, a 2D model which combines basic DBM and cone geometry describing the propagation of the CME leading edge which does not evolve in a self-similar manner; (4) DBEM, an ensemble version of the 2D flattening cone DBM which uses CME ensembles as an input; and (5) DBEMv3, an ensemble version of the 2D flattening cone DBM which creates CME ensembles based on the input uncertainties. All five versions have been tested and published in recent years and are available online or upon request. We provide an overview of these five tools, as well as of their similarities and differences, and discuss and demonstrate their application.
Highlights
Coronal mass ejections (CMEs) are one of most prominent drivers of space weather in the heliosphere
Propagation of coronal mass ejections (CMEs) in the heliosphere with the purpose of obtaining the time of arrival (ToA) and speed of arrival (SoA) of CMEs can be modeled by empirical models (e.g., Gopalswamy et al, 2001; Paouris and Mavromichalaki, 2017), kinematic shock propagation models (e.g., Dryer et al, 2001; Zhao et al, 2016; Takahashi and Shibata, 2017), machine-learning models (e.g., Sudar et al, 2016; Liu et al, 2018), numerical 3D magnetohydrodynamical (MHD) models [e.g., H3DMHD model by Wu et al (2011), WSA-ENLIL+Cone model by Odstrcil et al (2004), EUHFORIA model by Pomoell and Poedts (2018), CORHEL model by Mikicet al. (1999), or AWSoM model by van der Holst et al (2014)], and drag-based models
We note that the drag-based model (DBM) tools can be used to simulate both CME and shock propagation; it is important to keep in mind that:(1) the shock propagation is not necessarily coupled to CME propagation; (2) proper CME/shock input is used; and (3) lower γ values should be applied to shock as compared to the CME propagation
Summary
Coronal mass ejections (CMEs) are one of most prominent drivers of space weather in the heliosphere. One of the most popular CME propagation setups used in forecast models in recent times is the drag-based propagation In this concept, the CME, which is initially under the influence of Lorentz force, gravity, and drag force due to interaction with the ambient medium, at a certain distance from the Sun is influenced dominantly by the drag force (see e.g., Zhang et al, 2006; Temmer, 2016, and references therein). Starting with a basic 1D DBM (Vršnak et al, 2013), five versions of the drag-based model versions have been developed by the Hvar Observatory solar and heliospheric group in close collaboration with the solar and heliospheric group at the University of Graz
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
